Leading high street coffee chains have been urged to come clean about the amount of plastic waste they produce after they refused to release details about the number of throwaway cups sold in their shops.

Campaigners said the UK was in the midst of a “coffee cup nightmare” and urged major retailers to be “upfront” about the environmental damage they were doing amid a renewed focus on disposable cups.

The UK throws away 2.5 billion paper coffee cups every year, with just one in 400 estimated to be recycled.

The majority of those are sold by high street coffee chains, yet taxpayers foot the bill for processing 90 per cent of packaging waste.

Coffee cups are particularly hard to recycle because they contain a paper exterior with a plastic lining to keep the cup sealed.

As a result, almost all of them are incinerated, exported or sent to landfill.

Asked by The Independent how many disposable cups were handed out to customers every day in their UK shops, several of the country’s largest chains were unable to provide the figure. Those that were able to only did so after repeated requests for the information.

That response prompted environmental groups to warn of a lack of transparency among high street coffee vendors.

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The issue of coffee cup waste was highlighted last week by a group of MPs who urged the Government to introduce a 25p charge for disposable cups on top of the price of a coffee.

Some shops give money off the price of a hot drink for customers who use reusable cups, but the committee said uptake of these offers was low at only 1 per cent to 2 per cent of coffee purchases.

Costa, the country’s largest coffee shop chain with more than 2,000 cafés, said it was unable to provide the latest figures for the number of takeaway cups used because it was in a “closed trading period”.

Pressed to give an estimate, it referred The Independent to a submission to the Environmental Audit Committee from last April that showed it sold 76 million throwaway paper cups each year.

Starbucks, the UK’s second biggest coffee chain, said it was aware of the problem and was trialling a 5p charge for throwaway cups in a selection of its London shops – but failed to provide a figure.

Marks & Spencer was also unable to provide the data, but said just 3 per cent of all its hot drinks were sold in throwaway cups.

A spokeswoman for Pret a Manger, which recently introduced a 50p discount for coffee drinkers who bring their own mug, said she was unable to provide a figure but acknowledged it was likely to be a “big number”.

Julian Kirby, Friends of the Earth waste campaigner, said coffee chains must be “upfront and honest about their contributions to the problem, which means disclosing the amount of single-use coffee cups that they are releasing onto our streets every day”.

He told The Independent: “The last thing these companies want is to confirm what we all know, which is that every day they generate a colossal amount of plastic pollution.”

Caffè Nero said it got through 100,000 takeaway cups each day, but when asked how many the chain recycled, a spokeswoman said the “vast majority of the cups and lids we issue leave the store and are disposed of away from the original point of purchase”.

Sandwich chain Eat said it was unable to provide the figures on cups used, but added that it used compostable cups and was working with a supplier to provide compostable or recyclable lids.

Waitrose, which offers free coffee in its supermarkets for holders of its loyalty card, said it was an “industry-wide issue” and suggested enquiries be forwarded to the British Retail Consortium.

Fiona Nicholls, oceans campaigner at Greenpeace, said tackling the problem of plastic waste required “transparency and cooperation from business”.

“Taxpayers are paying to clear up a mess made by manufacturers and retailers, with just 10 per cent of the bill for disposing of packaging waste paid by business, and that needs to change,” she said.

Hugh Fearnley-Whittingstall, chef and environmental campaigner, said the UK was in the midst of a “coffee cup nightmare”.