Cabinet sources said the Chancellor made the claim at No.10, while in a heated meeting discussing new defence cuts with former Defence Secretary, Sir Michael Fallon.
He said that would be enough to send a division to fight a war, according to The Sun.
But senior military chiefs said that an army of that size would only be able to sustain any war for about six months.
Tory MP Johnny Mercer, a former Army officer, told The Sun: ‘We couldn’t even fulfil our Nato commitments with 50,000, let alone mount a sustained defence of our nation or its dependent territories.’
The Army is currently 4,000 short of what it should be, with 78,000 troops.
Cutting it down by 28,000 would make it the smallest it has been in 220 years and fall short of Germany’s 60,000.
This comes after allies of Chancellor Philip Hammond accused Defence Secretary Gavin Williamson (pictured) of stirring up a ‘bogus’ war on defence cuts to win over Armed Forces chiefs
Meanwhile it was reported that the pound’s low value against the dollar represents a big risk to Britain’s £9.1billion programme to buy 138 of the world’s most advanced war plane.
The UK has 13 F-35 fighter jets, made by American manufacturer Lockheed Martin, in the US being tested ahead of flight trials from HMS Queen Elizabeth next year, and plans to buy 138 more.
But the MoD’s most senior civil servant Stephen Lovegrove said he worries about how the foreign exchange position will affect defence procurement.
‘That is a big risk, that is a big risk right across the equipment programme, and clearly the biggest risk is against the dollar because we spend a lot more in dollars,’ he said.
Cabinet sources said the Chancellor made the claim at No.10, while in a heated meeting discussing new defence cuts with former Defence Secretary, Sir Michael Fallon