Pensioners in Scotland will escape losing their Winter Fuel Allowances after Tory protests that it is “colder”, Theresa May has agreed.

The Prime Minister has backed an exemption to the controversial plans to means-test the payments of up to £300, saying Scotland has the power to make “different choices”.

Ms May did not deny suggestions that ten million pensioners in the rest of the UK would lose their money, but insisted the “least well-off pensioners” would be protected.

The exemption for Scotland is certain to increase the controversy surrounding the proposal to means-test, contained in the Conservative general election manifesto.

North of the border, Scottish Secretary David Mundell pushed for different rules, telling The Herald newspaper: “The specific view in relation to Scotland is that, obviously we have different climatic issues.”

Launching the Conservative manifesto in Scotland, Ms May confirmed she had agreed to the plea, which allowed the document to read: “We will also maintain all pensioner benefits in Scotland.”

The Prime Minister said: “Social security devolution allows us to make different choices in Scotland and so we will protect universal Winter Fuel Payments for all older people and they will not be subject to means-testing.”

Ruth Davidson, the Scottish Conservative leader, said: “I am in charge of writing my own manifesto and always have been. Sometimes devolution means that you take a different choice.”

The move could cause difficulties for Conservative candidates in the North of England, which also has lower temperatures than the Tory heartlands in the South.

Significantly, Theresa May has made a determined pitch for Northern Labour seats – particularly those that voted for Brexit – launching her manifesto in Halifax, a Labour-held marginal.

The Conservatives have refused to say how many pensioners will lose the annual payments of up to £300, to help with winter fuel bills, when they are means-tested.

But it is expected that only the poorest, those claiming pension credit, will still receive them – which would mean ten million pensioners losing out.

Quizzed on the plans as she visited a haulage firm in North Berwick, the Prime Minster sidestepped questions about whether ten million pensioners would be hit.

“We are going to make changes for the payments of the winter fuel payments but we will continue to ensure that the least well-off pensioners are protected,” she said.

Scotland may be able to afford to keep the payments – as it has retained other benefits – because it receives much higher funding-per-head than England, under the controversial Barnett Formula.

Opposition parties condemned the latest twist. Andrew Gwynne, Labour’s elections coordinator, said: “When the Scottish Tory Leader comes out against her own party’s attack on pensioner incomes I think it’s fair to say the policy is starting to unravel.”

And Tim Farron, the Lib Dem leader, said: “The Tories are utter hypocrites. How can they take cash off English pensioners and then give it to Scottish pensioners? It looks like a cheap election bung.”