Tom Tugendhat heaped pressure on Rishi Sunak today as he warned defence spending must rise ‘now’.

The security minister gave the Prime Minister a fresh headache over funding for Britain’s military in a round of TV interviews.

He insisted defence spending should increase to 2.5 per cent of GDP ‘now… as soon as possible’, despite Chancellor Jeremy Hunt having ruled out an immediate rise.

Mr Tugendhat, an Iraq and Afghanistan veteran, made his fresh plea having last week broken cover to say the UK must ‘lead the way’ in boosting military funding.

In a joint article with Foreign Office minister Anne-Marie Trevelyan, he called for Britain to invest at a ‘much greater pace’.

Mr Tugendhat this morning refused to say whether Downing Street pre-approved the article.

At least a dozen ministers and MPs are said to have privately expressed support for his and Ms Trevelyan’s call.

It has also emerged how some Tories are so angry with Mr Sunak’s failure to boost defence spending in last week’s Budget they have nicknamed the PM ‘Neville Sunak’.

This is in reference to ex-premier Neville Chamberlain, who failed to stand up to Nazi leader Adolf Hitler in the run-up to the Second World War.

Tom Tugendhat heaped pressure on Rishi Sunak as he warned defence spending must rise ‘now’

The security minister gave the Prime Minister a fresh headache over funding for Britain’s military

Mr Tugendhat insisted defence spending should increase to 2.5 per cent of GDP ‘now… as soon as possible’, despite Chancellor Jeremy Hunt having ruled out an immediate rise in his Budget

Some MPs have nicknamed the PM ‘Neville Sunak’ in reference to ex-premier Neville Chamberlain, who failed to stand up to Adolf Hitler in the run-up to the Second World War

At the Budget – despite pressure from Tory backbenchers to boost defence spending amid ongoing conflicts in Ukraine and Gaza – the Chancellor would only promise to raise it to 2.5 per cent ‘as soon as economic conditions allow’.

During broadcast interviews on Monday, Mr Tugendhat declined to say whether Downing Street had cleared his joint article with Ms Trevelyan but renewed his call for urgency.

He told Sky News: ‘I want to achieve 2.5 per cent now, you know, as soon as possible.

‘First step to do is to get to the 2.5 per cent, and then we’ll have to adjust as the challenges we face evolve.’

Asked by Ed Balls, a former New Labour minister, on ITV’s Good Morning Britain whether he had to get the article cleared by Number 10, Mr Tugendhat said: ‘Ed, did you have to clear everything through Labour?

‘You probably did, actually, have to clear everything through Peter Mandelson, didn’t you?

‘Probably how your Labour Party worked, where everything was so tightly controlled.’

In a highly unusual intervention from two serving ministers last week, Mr Tugendhat and Ms Trevelyan used a LinkedIn article to warn the global risk posed by countries including Russia and China meant there was no time for delay.

‘The sad truth is that the world is no longer benign,’ they said.

‘Protecting ourselves requires investment. And effective investment means that our industrial complex must grow and strengthen at much greater pace than at present.’

They added: ‘It’s clear to us that the UK needs to lead the way in increasing our own domestic defence and security spending commitments to 2.5 per cent and beyond.

‘Former defence secretary Ben Wallace and prime minister Boris Johnson made inroads into growing our defence budgets, which had been shrinking in real terms for years, but that only filled the hole. Now we need growth.’

Downing Street today confirmed it did not sign off the article by Mr Tugendhat and Ms Trevelyan.

‘You wouldn’t expect us to sign off social media posts,’ said the PM’s official spokesman.

In the Budget, Mr Hunt said ‘our spending will rise to 2.5 per cent as soon as economic conditions allow’, but there was no detail of how that would happen.

This has caused a backlash within the Tories with one MP having reportedly told colleagues they would today hand in a letter to the 1922 Committee calling for Mr Sunak to be toppled over the issue.

One minister told the Daily Mail: ‘Across the board there’s a sense that we’re talking on the one hand about a more dangerous world but we’re not demonstrating what that means in spending terms.

‘Those of us in the know feel the threats are so many and various that it would be very hard to meet them all.’

A second minister said: ‘The Budget was underwhelming. We needed a better offer on defence. This is about values and we’re supposed to be the party of defence.’

Tory MP Danny Kruger, co-chairman of the New Conservatives group of MPs, said: ‘The Government is increasing defence spending, which is welcome.

‘But as Tom and Anne-Marie have said, we must work faster to restore our war fighting capabilities.

‘We need to make up for the false promises of the ‘peace dividend’ years and urgently reinvest in the Armed Forces.’

A senior backbencher said: ‘We have ministers publicly breaking ranks over defence cuts, a Chancellor who barely knows the difference between a tank and a helicopter, and party members who want to prioritise defence spending, even over tax cuts.’

Last night Liam Fox, who served under David Cameron, became the sixth former defence secretary to back more cash for the Armed Forces.

‘What we’re spending is not enough because of the level of threat out there now and the fact it’s a growing threat,’ he said. ‘I agree that at least 2.5 per cent is where we should be.’

In a Sunday Times interview, Mr Sunak defended his record on funding the military.

‘I would just point to our record here as chancellor when I oversaw the largest increase in the defence budget since the end of the Cold War with a £24 billion uplift,’ he said.

‘The whole point is, we recognised that the world that we’re living in was becoming more dangerous, and we had to invest more to protect the country against that.