/ Sustainability

Announcing the new ‘Which? Investigates’ podcast

Today, on World Environment Day, we’re launching a brand new podcast called ‘Which? Investigates’. Its host, Science Journalist & Producer Greg Foot, is here to tell us more.

I’m really excited to be hosting an eight-episode first season of ‘Which? Investigates’. The podcast looks to uncover which of the myriad claims we all see on products, in the press and shared on social media are actually backed up by facts.

The first season of Which? Investigates focuses on putting claims of “sustainability” under the spotlight.

From plant-based food to plastic-free products and electric cars, I’ll be digging deeper into what genuinely reduces our environmental footprint, and what’s simply green-washing, to give consumers the confidence to make better choices for themselves and the environment.

Which claims can we trust?

It all started when I read on Twitter that removing plastic packaging from some foods may actually increase their environmental impact rather than reduce it.

I then heard that some of the plastic I diligently check, wash and recycle at home may end up being shipped thousands of miles away where it’s dumped or burnt.

Another curve-ball arrived when I showed a friend my new electric car and she pointed out that the batteries use loads of rare earth metals and that manufacturing the car comes with a big environmental cost. ‘So’, she asked, ‘shouldn’t you have just kept your old gas-guzzler?’

That was a fair question, and it’s exactly the sort I’ll be trying to answer in the podcast.

Filtering out marketing hype

For a while now I’ve been on a mission to separate genuine claims from marketing hype, calling on brands and manufacturers to provide evidence for the bold statements they make on packaging, in the press, or on social media. 

I started this bunk-busting with my BBC Radio 4 series “The Best Thing Since Sliced Bread?” where I scrutinised claims about kombucha’s ability to make your gut healthier, exercise tape’s effectiveness in supporting your joints and “noise-cancelling” headphones success in, well, cancelling noise. 

I’ve always wanted to dig deeper into ‘sustainability’, to find out what genuinely reduces our carbon footprint and what is actually just marketing, and this podcast is going to do just that.

If you’ve ever been told that you should go vegan for the planet, or heard that you can holiday with a clear conscience if you carbon off-set your air miles, and were left wondering what the evidence says, Which? Investigates is here to help.


Apart from the scarce rare metals argument, building an EV isn’t quite the monster many fossil fuel adherents would like to paint it. And vehicle building of any sort is an intensive process, consuming a lot of resources.

But the best two things about an EV are that once built it no longer pumps out lethal gases, a major issue in the big cities and, secondly, it’s very quiet.Those two aspects alone place it head and shoulders above fossil-fuel vehicles, as they belch Carbon monoxide, Hydrocarbons, Particulate matter and Nitrogen oxides, each of which is damaging to health and particularly so for children.

Thanks Ian, it is exactly these kind of things we will be addressing when we look at electric cars in episode 3.

Rodney Brown says:
18 June 2021

The Fuels of the future will be Hydrogen, Ammonia and bioMethane (The later made from your No 2’s.)Hydrogen extracted from seawater is already in use for Heavy Trucks in U.S.A. and a new Test Ship, carrying and powered by liquified Hydrogen in Japan. However Hydrogen is unlikely to fuel cars. Hydrogen and Ammonia are already in use within industrial Plants.It will be a fuel for Ships and Passenger Aircraft. bioMethane produced in U.K. sewerage plants is already used for their Plant vehicles, and a test road vehicle is operational. A point to remember however is that batteries (and motor cars) do not last forever (ref also Nuclear Power Stations). An environmentally friendly scrapyard has not been invented. A good point to bear in mind is that the 1st, motor car’s initial fuel was alcohol. Auto Driving vehicles may become essential.

I do not have time to read anymore of this sort of stuff.

The batteries seem to be where the problem lies. Extracting the materials needed to make them is a polluting process and apparently disposing of old batteries may not be environmentally friendly. No doubt legislation can deal with the latter in responsible countries.

Pollution depends upon the source of energy. Gas still accounts for a fair proportion of the UK’s electricity generation and, as a fossil fuel, produces CO2. So EVs are not non- polluters, even if indirectly.

Their key benefit is certainly not emitting in built up areas. A great benefit to health. Looking forward, though, these are areas where “clean” public transport could play a much more dominant role. We could need far fewer personal vehicles if that were tackled.

Thanks for introducing the new series of podcasts, Greg. As pointed out in the first episode the issue of single-use plastic is complex because single-use plastics can save a great deal of food waste as well as being damaging to the environment. In my opinion, manufacturers and retailers should be advised on best practice.

We are hearing mixed messages about electric vehicles, which Ian has mentioned. What is very clear to me is that we must stop using diesel and petrol cars in cities with serious pollution problems. Whether we drive or use public transport, we can all help by reduce travelling for work or pleasure. After driving many miles to support a charity based 20 miles away I have decided to focus on helping a local one, only two miles away.

Many initiatives to reduce our impact on our environment seem to involve buying more stuff. Anyone considering buying new products that are more efficient should consider the impacts of manufacture of new products and disposal of old ones. If there reason for replacement is that it has broken, then have it repaired or do this yourself, which can often be done at little or no cost.

Really excited to see this podcast go live and looking forward to what’s getting discussed in future episodes. It was really interesting hearing about Rob’s experience of supermarket shopping as would love to see more stores offer this kind of option but I think until it’s rolled out on a large scale, uptake will remain low.

Francis Golden says:
5 June 2021

Though not germane to the above. Which’s view on “look after my bills” would be interesting

I look forward to the plant-based food podcast.

It is widely reported that the rainforest is being destroyed to provide crops to feed cows. The number of cows in the world is reducing but the number of vegans/plant-based eaters is increasing. Where is all the extra land coming from that is needed to grow this hugely inflated demand? Animals can graze on land that cannot be utilised for crops.

What was fed to Daisy the cow in the experiment?

Extra land is also needed to grow materials for plant-based packaging that is on the increase.

Phil says:
6 June 2021

Also for biofuels. The amount of biofuel, ethanol, in petrol is to be doubled from 5% to 10% later this year to the detriment of older vehicles. Electricity generation also uses large quantities of ‘biomass’, AKA wood, which is shipped across the Atlantic.

Good point Phil.

There needs to be some real honesty about where all these ‘new’ eco plant products are grown, fed, watered, disease & pest control, processed, transported and packaged.

And also how honest are all the claims of sustainably-resourced. They can’t all be telling the truth.

Bioethanol in petrol has resulted in damage to carburettors in many small petrol engines and biodiesel has caused other problems for diesel engines and with storage of diesel fuel.

Shipping biomass from North America cannot be described as sustainable but on the other had it’s much better than burning coal – certainly for those of us who are affected by sulphur dioxide.

Burning biomass is only less bad then burning coal. It emits a lot of CO2, requires long distance transport, and can only be regarded as carbon neutral if equal amount of plants are grown that can absorb the same amount of CO 2 as that emitted. In the case of trees that can take 20-30 years.

Surely it is far better to simply plant more trees in the first place to absorb CO2, and not burn them at all. That would be a net gain in CO2 absorption to help offset other emitters.

Of course, but we need to generate sufficient electricity and hopefully biomass will be phased out when we have better alternatives. I do not know how practical it would be to increase the number of trees but hopefully this will be explored. There’s plenty of scope to make homes more energy efficient.

”I do not know how practical it would be to increase the number of trees ”.I seems to me very simple – grow small saplings and plant them. But we need governments around the world to buy into increasing permanent vegetation to capture some of the excess CO2.

Resorting to burning wood just puts off the decision to develop more sustainable energy sources. Tidal energy can be used as flow and storage, is predictable and clean. Time we added this to the arsenal. We cannot rely on sun and wind alone; nuclear takes ages to construct and many believe it is far from clean.

Storage of nuclear waste could become a major problem in the future.

We also need to hope a tsunami won’t hit the Bristol Channel and we end up with another Fukushima. It was thought one killed around 2000 people in 1607.

But it is designed to withstand an aircraft crashing into it.

That’s all right then.😖

Malcolm wrote: “Tidal energy can be used as flow and storage, is predictable and clean.” Indeed it is. Projects such as the Severn Barrage have been opposed on good environmental grounds. I had not found similar strong opposition to harnessing offshore tidal power, but recently I was speaking to someone who is working for one of the major energy companies that is involved in trialing hydrogen/natural gas blends. He told me that the cost of offshore tidal power is currently too high. We might have to invest a lot of money to keep the lights on.

Many projects disturb the environment and always have. HS2 is destroying ancient woodlands, habitats and homes, Hinkley Point C occupies around 4 sq km of land and goes down to the bedrock; it will suck in and discharge huge volumes of water from the Bristol Channel for cooling. I expect with tidal storage habitat will adapt; it should not alter the water level significantly, but control it to generate electricity when it is needed.

If we don’t explore all green energy production and the planet continues to degrade, the wildlife will suffer as much, maybe more, than us. I’d suggest it is in their interests to share the initial upset.

Phil says:
7 June 2021

Tidal schemes will come with a hefty up front capital cost which has to be recovered but the recent Severn Barrage proposal was, allegedly, more than a bit dodgy.

Or was it the Swansea barrage? A lot about the shenanigans surrounding that proposal in Private Eye that exposed it as a money-making venture, except for the consumer.

Phil says:
7 June 2021

Swansea yes, my mistake. Bloke was demanding £168/kwh at a time when the market price was c.£48 and Hinkley Point was priced at £95. Accusations of lucrative contracts awarded to company run by his wife and stone to be bought at inflated price from quarries that he owned.

Em says:
7 June 2021

Can someone explain the concept of offshore tidal energy please?

My understanding (based on my limited research) is that a tidal power generator needs more than a one metre head of water pressure and a reservoir of water lasting several hours to do anything useful. High and low tide heights are mostly determined by surrounding land masses which restrict the flow of water, and the sustained water flow necessary is achieved by barraging an estuary or similar land-based geographical feature.

Mid-ocean tides are no more than one metre and without a large mass of captive water, I don’t think water rising and falling by one metre every 12 hours or so is going to generate anything worth having. As someone on The News Quiz suggested the other week, maybe Dyson could invent a way of extracting power from drizzle.

Hi Em, see:-https://www.bbc.co.uk/news/uk-scotland-tayside-central-56818538 for one recent example.

”Tidal streams

Tidal stream generators are essentially wind turbines designed for underwater use. While tidal barrages can take a long time to build, tidal stream generators, more commonly known as (TEC) tidal energy converters, are much faster to deploy because of their free-standing and independent nature. Unlike the full scale commitment required by tidal barrage projects, operators can easily test the waters with standalone test tidal stream turbines.

Unlike wind turbines, tidal turbines have a higher power output potential than equivalent wind energy counterparts. This is because water is 800 times denser than air which means that even at low tidal flow speeds a tidal turbine will still keep on churning, unlike its wind turbine relatives which are more likely to just sit pretty with low wind speeds.”

Em says:
7 June 2021

Thank you for the clarification. What threw me is the term offshore. Since, by definition, all tidal power solutions are immersed in water, I took this to mean generation plants that are in deep water locations at some considerable distance from the shoreline, where tidal effects are almost non-existant.

Marko says:
13 August 2021

Livestock takes up nearly 80% of global agricultural land, yet produces less than 20% of the world’s supply of calories. You could reduce the land available to livestock by 25%, and double the amount of calories produced by the total amount of land. Reducing the land allocated to meat production can only help, there are no systemic downsides (though there may be temporary, local pain associated with change).

If we are going to have to stop using plastic there will be a return to leather for certain purposes. If we want leather then we might as well have the meat [and other by-products] that goes with it and makes it economical. Unlike plastic it is renewable and sustainable.

There are more chickens in the world than humans – 19 billion apparently. And parts of many seem to be eaten in the US of A ”Roughly 28 million pounds (13,000 t) of chips, 1.25 billion chicken wings, and 8 million pounds (3,600 t) of guacamole are consumed during Super (Bowl) Sunday (2020).” Can this be true? Wiki says so and they were among the interesting bits of information uncovered on Richard Osman’s House of Games.
I have never seen the attraction of eating a chicken wing that seems to be largely bone and skin.

Thanks for the podcast Greg, I have just listened to it.

It is interesting that packaging can give some products a longer life i.e. cucumbers. On the other hand plastic can make food sweat and go prematurely rotten if the contents are not removed or at least breathing holes made in the plastic.

There ought to be a survey on carrot wastage. If I go to a supermarket, I will choose 3 or 4 large loose carrots that I know will get used. But buying in lockdown means I have to accept what the supermarket offers – Ocado in my case. Nearly every week despite my efforts to use them, some go to waste. I did try freezing them, but they don’t freeze well and certainly can’t be used to make home-made coleslaw. Removing them from the plastic and wrapping in slightly damp kitchen roll seems to work best.

I tried an experiment this week and stood some limp carrots in a jug with a small amount of water in the bottom and put them in the fridge. You can revive lettuces this way so why not carrots I thought. After a couple of days they were slightly less limp, but with no real root left on the carrot it didn’t really work.

Carrots are sold in much too large quantities and are usually very small and fiddly, not good if you have problems with your hands or fingers. If they were allowed to grow larger and sold in smaller packs, a lot less would need to be produced and a lot less would go to waste.

Supermarket carrots are often heavily scrubbed to make them look nice and clean and orange, but that makes them more vulnerable to deterioration. Keeping carrots in a sealed plastic bag will result in deterioration but in paper they could become limp because a fridge is a very dry environment. It’s a compromise, but one thing that will help is to keep the fridge as cold as possible without anything freezing. I have just used some Morrisons organic carrots dated 28 April and they were fine, but they had not been heavily scrubbed.

Carrots don’t survive home survive home freezing well (blast-freezing is used commercially) but I wonder if you could grate and freeze them, Alfa.

I agree that it would be worth having a discussion about how to avoid food waste.

I have tried freezing grated carrot but it turned into mush when thawed out. Parsnips don’t freeze well either.

Jacket spuds on the other hand freeze really well. I had too many so cooked them in the microwave then froze them. Defrosting in the microwave then finishing off in the oven and they are really good.

Before lockdown, we would just select and buy what we needed, shopping several times a week if required so there was rarely any waste, but have had to adapt to a delivery once a week and buying more than we need simply because smaller packs are unavailable.

I haven’t tried it out yet, but I recently noticed Waitrose are selling loose carrots for home delivery that would greatly cut down on waste.

I will bear it in mind that jacket potatoes can be frozen.

If you can find carrots that have not been heavily scrubbed it would be a help. I suspect the ones with the tops attached would be best but then you need a rabbit to deal with the greenery.

I do agree that we need to tackle food waste.

The carrot tops are going to be ‘wasted’ wherever the preparation takes place – on the grower’s premises, in the cannery or frozen food factory, or in the restaurant or domestic kitchen.

They can be used for compost in each case and are probably more likely to be used that way than if the tops are cut off at home and there is no food waste collection or composting. All vegetables produce an excess of greenery – it’s just that the consumer rarely sees it with potatoes, sprouts, peas, root vegetables, tomatoes and some salad crops. Just look at the amount of waste with sweetcorn! It is likely that the most efficient production and processing systems will make the best use of this vegetable matter and it will be reprocessed for bio-fuel, oils, animal feed, insulation, fabric or fibre, or compost. There should be no landfill or incineration.

The well-prepared soil for root crop production generally gives a very clean crop. Carrots do not need to be scrubbed; that is purely for presentation purposes. They should be washed before eating and boiling will destroy any residual dirt. I don’t think it is necessary to scrape or peel the skins off potatoes.

The customer has to pay considerably more for carrots with their tops attached, but at least they should be fresh, otherwise the greenery would be wilted. It is unlikely that they are scrubbed because that would be difficult with the tops attached.

Of course carrots don’t need to be scrubbed and it’s well established that unwashed ones will last longest.

I think many people are frustrated they are doing as much as they can to recycle but their efforts are curtailed with problems Ellie touched on in the podcast.

Councils do their own thing. Some recycling is sorted kerbside, others go in a bin for mass sorting. Some collect Tetra paks, others don’t. There is much confusion over what can and cannot be put in your recycling bin. Then there is packaging that can only go to specialist sites such as Terracycle that you have to go out of your way to dispose of.

We have said it here many times before, but there needs to be standardisation across the whole country with dedicated processing plants to make the most of our recycling and reuse of household waste packaging. Until this vital step is set up, too much will still go to landfill or incinerated.

Hi Greg and other Which staff

Would you agree that marketing hype is allowed by law, being called Puffery?

And that if you want to get rid of hype and make adverts only state facts, you need to campaign to change the law and ban Puffery?

Well said a.

In law, puffery is ‘a promotional statement or claim that expresses subjective rather than objective views, which no “reasonable person” would take literally’.

There is a conflict between false claims and consumer law which says that goods and services must be as described and that descriptions must be fair and honest, so the “no reasonable person” condition might provide a defence that an obviously exaggerated claim could be exempt from the usual rules of contracts and is not necessarily unlawful. I feel that such a claim would have to be so outlandish as to be ridiculous in order to evade an accusation of puffery.

We don’t ned to change the law. We need to make it work for consumers by challenging all plausible but false claims. Most reasonable people are also gullible to some extent.

Gerald Ratner adopted a refreshingly down to earth approach: https://www.youtube.com/watch?v=sKtBkVrqYYk It is sad that not everyone had a good sense of humour.

Not a regular commenter, but I am a listener of many a podcast and enjoyed this one – thanks to Greg, Ellie and the team.

Greg Foot’s second podcast was can be found here: https://play.acast.com/s/which-investigates/doesyourphonecomewithanexpirydate-

In other Conversations a few of us have discussed the frequent replacement of smartphones and the short support for certain makes and models, which has security implications. What I had not realised until today is how little of the valuable materials that are used in smartphone manufacture are currently recycled. Yes it makes sense to pass on unwanted phones to others or to charities that an use them.

There is considerable pressure, particularly in the US for companies to make spare parts and service information available to consumers. Apple supports its phones for considerably longer than the other major manufacturers but will not sell spare parts, other than chargers, cases, etc. to owners. This resulted in me scrapping a phone. My iPhone 5s was approaching five years old and the battery was starting to deteriorate. I somewhat reluctantly bought a third party battery of unknown quality and it worked very well for two months before it deteriorated rapidly. After I had consigned it to my ‘tech drawer’ (as Greg has called the place where we keep our unused and broken gadgets). Soon after, I discovered that the failed battery had swollen so much that it had burst open the metal phone case:

I have found Apple products extremely reliable and their customer service extremely good on the odd occasion when I have needed help, but I hope the right to repair movement will show Apple who is boss.

None of the popular smartphones has a simple user-replaceable battery and replacing modern phone and tablet batteries often involves heating the glass to melt the glue that holds them together. I believe we need legislation that requires batteries to be user-replaceable, just like phone batteries used to be.

I am now on my second iPhone and hopefully this one will last for at least five years too. Like its predecessor it was bought from the manufacturer and used on a SIM-only contract, so there is no pressure to replace it before I want to.

It would be good if Greg could have a look at the electronics right to repair issue in a future podcast to help make us all aware that manufacturers are preventing us from repairing our tech products, even down to selling us a replacement battery.

What about health problems reportedly associated with the electro magnetic fields produced by electric cars that may affect drivers and passengers (and, possibly, even pedestrians in regular close proximity to an ever increasing number of electric vehicles)?
I am aware that some manufacturers have said that there is “no scientific evidence” that electric magnetic fields in cars can be injurious to health – but I do wonder ………..

Hi Rod, I doubt that the electro magnetic fields produced by electric cars will differ from those on electric trains or trams or from those produced by certain home appliances, e.g. hoovers.

If you have seen reports suggesting otherwise, can you post links to them here?

Long ago, I used to design magnets and electric motors, so I’d be keen to have a look.

If there is evidence of electromagnetic fields affecting our health there is scope to reduce these fields but first we need to see evidence that there is a problem.

And there I was hoping that with a powerful electro-magnetic field in an electric motor car we would be able to change the traffic signals to green on our approach and send other vehicles into a tail-spin to clear all the roundabouts on the ring road.

Don’t Mercedes and Audi already offer those as part of their built in right of way options?

Martin says:
4 July 2021

Is bamboo sustainable and a good replacement for cotton?

Yes, Martin – In many ways it is a good substitute for cotton and has several advantages over cotton. It is certainly as sustainable as a raw material for textile manufacture but does require a lot of water, however its prolific root structure helps prevent soil erosion. Its high density and rapid growth compared to cotton give it a much higher yield per hectare so it is a very efficient crop. I don’t know whether over the long term and for durability bamboo is a more economical material than cotton, which is usually regarded as a high cost fabric compared with synthetic textiles, but the economic balance of natural against synthetic fibre is probably changing now and if sustainability is the objective then bamboo [and cotton] should be favoured.

Maybe we could make more use of flax to produce linen. It seems to use little by way of resource. https://www.independent.co.uk/news/business/bid-to-restore-fibre-to-uk-flax-industry-1573790.html

I cannot read the full article [because I am not willing to register with The Independent] but I recall reading about the rejuvenation of the British textile fibre industry not long ago. Linen made from home-grown flax was a staple product and major export of Northern Ireland.

I strongly support the use of flax to make linen but it has become quite an expensive material. Other materials like cotton and polyester [in various percentage combinations according to their properties and costs] have supplanted linen. Linen is a very strong and durable fabric but has gone out of favour because it is heavier, colder, and requires more intense laundering and ironing than cotton and poly/cotton. I prefer it as a bedding material, it is excellent for table covers and dinner napkins [and looks better in damask form than other fabrics], and it makes by far the best tea towels because it is so absorbent and dries faster than cotton. Linen is also good for clothing, aprons, and especially shirts and dresses owing to its comfort properties in hot weather. Its tendency to crease and wrinkle is regarded as a feature for casual attire.

I should also like to see jute return as a furnishing textile instead of synthetic materials. The raw material used to be imported in large quantities as a return load from India in ships to Great Britain [mainly Scotland where Dundee was the centre of the worldwide jute industry] for manufacture into all kinds of strong material where its heavy, tough and coarse natural properties were required such as mats, backing for carpets and linoleum, upholstery fabrics, sacking, and baling twine. It could make a comeback for all manner of hardwearing applications where the usual choice is currently plastic.

Just listened to the EV podcast and you have produced one of the best and well balanced reviews that I have heard. I have been driving BEV since 2015 -Leaf then Model S now Model 3 LR and have been driving to Portugal every year to visit family since 2017. It’s got easier each year with the Tesla charging network and really pleased to hear they are opening it to other EVs. I also have solar and ASHP at home – no gas here since Feb 2020.


Why haven’t we been made aware of the new podcast episodes and had a convo on them for discussion?

I have just listened to episode 4 of this series and would very much like a convo on it.

It would also have been good to have Greg Foot participating in discussions.

Work in progress on this one @alfa – we’re working with the podcast team on this with the aim of W? Conversation in the autumn especially, and also had something separately in the works on plant-based diets specifically. It’s a good episode, that one.

That being said, why not start the conversation now? Feel free to use this discussion or in the latest Weekly Roundup , as that space is aimed at what’s going on right now (latest podcasts included).

What were your thoughts?

It was interesting but I was disappointed that as usual, most of the supporting evidence was one-sided from vegans although we did hear from a sports trainer who rather contradicted the Netflix documentary Game Changers.

I don’t quite see the point of posting in the Weekly Roundups as they are quickly closed off to new posts, none of the data can be searched for so useful information will soon be ‘lost’.

I would advise anyone contemplating a vegan diet to see a nutritionist first, to ensure you are consuming the correct amount of vitamins and minerals to suit you as an individual. It is vital for people on certain medication, as embarking on a different diet can affect the amount or type of meds prescribed, sometimes with dire consequences.

Absolutely right. There is a big difference between eating a vegetarian diet and a more restrictive vegan one.

A nutritionist is qualified to do their job: https://www.healthcareers.nhs.uk/explore-roles/wider-healthcare-team/roles-wider-healthcare-team/clinical-support-staff/nutritionist Others, for example nutritional therapists need not be and I have seen highly questionable advice on websites, even our nutritional therapy discussions on Which? Conversation.

Those who choose a vegan diet have to be much more careful than vegetarians about supplementing their diet to provide adequate nutrition. For example, a vegan diet contains no vitamin B12, which is found mainly in meat, dairy products and eggs.

Just finished listening to the last episode and found the topics very interesting, especially about where your pension investments are made.