A rail operator has done a U-turn and agreed to let passengers use their own reusable cups for hot drinks bought on board its trains after criticism by environmental campaigner Hugh Fearnley-Whittingstall.

South Western Railway changed its policy after the chef complained on Twitter during a journey that buffet car staff – employed by catering company Rail Gourmet – had “refused” to pour tea into his refillable cup.

Rail Gourmet on @SW_Railway just refused to make me a cup of tea in my keep cup - saying it’s company policy to use the cups provided. I’ve asked on many other trains (inc Great Western and Cross Country) and this is the first time I’ve been refused. ☹️ #WasteNot #WaronWaste 🌍 pic.twitter.com/vKoPdwbYeN — Hugh Fearnley-Whittingstall (@HughFW) November 22, 2018

Twitter users fuelled the row by questioning the company’s policy, amid mounting concerns over the overuse and scale of wastage from single-use disposable cups and their impact on the environment.

It is estimated that about 2.5bn disposable coffee cups are used in the UK each year. Although poly-coated paper cups are technically recyclable, few facilities are capable of doing so. This means that most end up in landfill, creating about 25,000 tonnes of waste each year. Half a million are thrown away each day in the UK but just one in 400 are recycled.

The campaigner – who revealed the vast scale of waste from coffee cups in his War on Waste TV programme in May 2016 – claimed he was told it was “company policy” to only offer disposable coffee cups – which cannot entirely be recycled.

On Twitter, the company apologised to the celebrity chef and said there was a “safety aspect” involved in the decision.

A spokesman for South Western Railway confirmed the change in policy: “We have been discussing the use of customers’ cups with our catering contractor, Rail Gourmet, for some time. We have now agreed that customers’ own cups can be used onboard our services for hot drinks. This will be implemented onboard as soon as possible. This reflects our ongoing commitment to manage our environmental impact.”

Meanwhile, other rail operators, including Greater Anglia, are updating their policies and machines to cater for the growing popularity of refillable cups.

A spokeswoman for Greater Anglia said: “Customers can use their own cups for tea and micro-ground coffee and receive a 20p discount. Drinks which require the coffee machine (lattes, cappuccinos etc) can not currently be served in customers’ refillable cups as a majority do not fit under the machine. We are replacing every train in our fleet with a brand new one. When the new trains arrive, all hot drinks can be served in refillable cups.”