Tobias Ellwood today warned China and Russia will be "breathing a sigh of relief" at the UK's defence spending announcement. The senior Conservative MP, who chairs the Defence Select Committee, said the British Army had been "hollowed out" and that the £5billion pledged by the Prime Minister would not go far enough.
Mr Ellwood, a former soldier, told Sky News: "Perhaps we've failed to make the connection between our economy, our prosperity and our wider security.
"The world is getting more dangerous, not less, we're seeing China and Russia start to morph together as an alliance.
"I'm hugely concerned that whilst I welcome the extra funding for our nuclear deterrent and indeed to replenishing the stocks of weapon systems and ammunition that have been provided to Ukraine, we're doing nothing to reverse some of those cuts that came in the last defence review.
"We saw our armed forces drop by 10,000, tanks, armoured fighting vehicles and so forth, even ships and planes were cut as well. So all three services are too small but particularly the army is being hollowed out.
"The Defence Secretary wanted double this amount just to stay level, just to keep his head above the water, and we've only got half of that.
"The next couple of years are going to get very dangerous indeed.
"This year particularly will be critical for Ukraine and Britain has done brilliantly in stepping forward because we've become rather risk averse, too timid, in dealing with aggressive nations such as Russia and China.
"But we can only do that with the hard power and I think Russia and China will be breathing a sigh of relief we've not invested further in our armed forces at this time.
"We are at the foothills of another Cold War. Globalisation in its current form is actually dying and it's countries like Britain that usually step forward and other nations follow. We can only do that if we invest further in our defence."
Mr Ellwood's comments were echoed by Lord Dannatt, a former head of the British Army.
The ex-chief of the general staff said the army is "woefully underfunded", adding that the UK will be in "danger" if more money is not invested.
He told Times Radio: "With a land war in Europe, our land forces, our army, is woefully under-invested and underfunded at the present time, everybody knows that the army has taken the lowest priority in spending terms for quite some time to come.
"So a pledge to go to two and a half percent of GDP is good. But my question is when? And what will that extra money be spent on?
"And I would say this, because I'm one of the blokes that used to run the army, frankly we should be spending more on our army. And there are lessons from history to show that if we don't, we stand in danger."
It comes as the PM yesterday insisted the UK's armed forces had the funding they needed for a "more volatile world" in the face of the growing challenges posed by China and Russia.
Significant sums of the promised new money will be swallowed up by replenishing ammunition stockpiles handed to Ukraine and work on the Aukus project to develop nuclear-powered submarines for Australia.
The funding is only around half of what Defence Secretary Ben Wallace had reportedly demanded as the military budgets are squeezed by the impact of Vladimir Putin's brutal invasion of Ukraine and high inflation, although officials said he was "delighted" with the settlement.
As the Government sets out the 2023 integrated review refresh (IR23) on Monday, Mr Sunak is visiting San Diego, California, for talks with Aukus allies US President Joe Biden and Australian Prime Minister Anthony Albanese.
Speaking on the USS Midway museum ship in the Californian port, Mr Sunak said: "It's clear that the world has become more volatile, the threats to our security have increased.
"And that's why we're investing £5 billion more in our world-beating armed forces over the next two years and increasing our defence spending to 2.5 percent of GDP so we can continue to be a world leader when it comes to defence and keeping our country safe."
The promised funding will see an extra £1.98 billion this year and £2.97 billion next year for defence.
Mr Sunak said the extra funding would take spending from 2 percent of GDP in 2020 to 2.25 percent in 2025.
"At that point, we will set out the trajectory for the next phase," he said, with an ambition of reaching 2.5 percent.