Rachel Reeves has signalled her unwillingness to raise taxes to pay for increased defence spending having already hiked the burden “substantially”.

The Chancellor said she “would prefer not to have to do that again”.

The Labour Cabinet minister also insisted she had “provided the biggest uplift of defence spending since the end of the Cold War”.

Ms Reeves argued the focus should be on how the money is spent rather than on the “quantum” of cash.

She made her comments after a prominent member of her own party and a former Nato chief accused the Government of “corrosive complacency” on military spending.

Former defence secretary Lord Robertson of Port Ellen led the Government’s strategic defence review, which looked at the threats Britain faced and the capabilities needed to meet them.

Speaking in Washington DC, where she is attending a summit of the International Monetary Fund, Ms Reeves said: “I’m proud to be the Chancellor that provided the biggest uplift of defence spending since the end of the Cold War.”

She pointed out she had taken money from the overseas development budget in order to increase defence spending.

Ms Reeves said: “National security always comes first, and I will always do the right thing as Chancellor to protect our country.”

She added: “The biggest beneficiaries of my spending review last year were the NHS budget and the defence budget. Both of those saw big uplifts reflecting the choices that we’re making as a government.