Kemi Badenoch has accused Andy Burnham of “fiddling while Europe is at risk of burning” as Russia ramps up its aggression towards allies of Ukraine.

The Tory leader said the Prime Minister should “get serious” and offer “proper” funding for defence while former military chiefs sounded the alarm over increasing threats faced by Britain.

The UK has promised to commit 3.5% of national income on defence by 2035, in line with a pledge by Nato members.

The Government has budgeted to hike defence spending to 2.7% of GDP by 2027-28, but faces pressure to set out firm details on how further increases will be achieved beyond then.

“Our Government is fiddling while Europe is at risk of burning. In France and Poland, leaders are taking action now against the growing Russian threat,” Mrs Badenoch told the Telegraph.

“What is our Government doing? Has anyone heard from Wes Streeting, the former head of the National Union of Students, who has rocked up as Defence Secretary?”

She added: “We have to stop pretending that we are living in a carefree end of history when Russia is testing our resolve week after week. It’s time to get serious.”

Mrs Badenoch said the Prime Minister was sending a “dangerous” message that he would not cut welfare to fund the military, which she said was “heard loud and clear in Moscow as well as Manchester”.

The Tories have heightened their attacks over over welfare spending in recent days after Mr Burnham said national security cannot “come at the expense of social security”.

Downing Street insisted he was committed both to funding the military and bringing down the benefits bill, but not through “crude cuts”, following the remarks at Prime Minister’s Questions last week.

Meanwhile, Admiral Lord West, the former First Sea Lord and security minister under Gordon Brown, told the paper that Britain’s military was in “quite a parlous state”.

“In many ways, one could argue we are already at war. We are certainly in the grey zone – whether it’s cyber attacks, drones getting near the edge of somewhere or threats to underwater cables,” he said.

Urging Chancellor and former defence secretary John Healey to set out a path to 3.5% at the Budget, former chief of the general staff Lord Dannatt said: “My bottom line is that Andy Burnham, and regretfully I would now add John Healey, are playing fast and loose with the nation’s security.”

Mrs Badenoch has said she would increase defence spending to 3% GDP by 2030 by slashing the welfare bill – a policy which the Prime Minister says would create “levels of homelessness” the country has never seen before.

The Conservatives have proposed capping housing benefit to raise £4 billion to spend on defence and rejected suggestions the move would make people homeless but suggested some would have to “move somewhere cheaper.”

A Foreign Office spokesperson said: “These threats from Russia are yet another attempt to distract from their barbaric invasion of Ukraine.

“We have been clear that Russia’s hybrid attacks are egregious and unacceptable.

“That’s why we have taken tough action to respond to Russia’s intensifying hostile activity against our continent – increasing defence spending, expelling intelligence officers, sanctioning the GRU, cracking down on illicit finance networks, and ensuring Russia’s criminal proxies are disrupted and brought to justice.

“The UK is united with our allies on the importance of defending ourselves, and Russia’s aggression will not deter us from supporting Ukraine.”