Rishi Sunak has insisted he wants to cut taxes just 18 months after he broke a key Conservative manifesto pledge by hiking national insurance.

In a speech ahead of the Autumn Statement, the Prime Minister this morning declared: "I want to cut taxes, I believe in cutting taxes."

The Conservatives vowed at the last election that they would not raise income tax, national insurance or VAT, but as Chancellor Mr Sunak last year increased national insurance as he took the country to its highest tax burden in 70 years.

In a desperate bid to paper over his record, it is thought his Government may announce a cut in national insurance on Wednesday as Jeremy Hunt sets out tax and spending plans in the Autumn Statement.

Mr Sunak today said he believed in cutting taxes "carefully and sustainably" as he gave an update on the economy. "We can't do everything all at once, it will take discipline and we need to prioritise, but over time we can and we will cut taxes," he told an audience at a college in Enfield, North London. Despite breaking his previous promises on taxes, the PM said his message to the nation is: "You can trust me."

It came as a leaked recording emerged of Paymaster General John Glen suggesting that many pensioners don’t need their winter fuel allowance. Shadow Chief Secretary to the Treasury Darren Jones has written to Chancellor Jeremy Hunt to demand to know what discussions ministers have had on stripping pensioners of their payments.

The Labour frontbencher said: “Pensioners will be deeply concerned about such speculation, especially ahead of winter, and anxious that their incomes may be under threat from this government. Pensioners are already having to contend with dramatic increases to the cost of living, particularly when it comes to their energy bills.”

Mr Glen, who was chief secretary to the Treasury at the time of the recording last month, also questioned whether the triple lock which guarantees increases in the state pension was sustainable. The minister, who became the Paymaster General in last week's reshuffle, was speaking at a Cambridge University Conservatives event on October 26.

In comments obtained by the Telegraph, he said: "I think we also need to come to terms with the fact that the triple lock is very expensive and how sustainable is that going forward in terms of pensions and all the other benefits? Because my mother, she's not very rich but she's perfectly comfortable. She just texted me today aged 75 to say 'I've just heard about my £500 winter fuel payment' and I'm just like 'you don't need that'... These are the sorts of things I think we need to look at."

The Treasury this morning ruled out a change to the winter fuel allowance in the Autumn Statement, with a spokesman saying: "This is not something we are going to do."