Britain's Army would be destroyed in as little as six months during a major war, Veterans Minister in the Ministry of Defence Alastair Carns said.

The Labour MP for Birmingham Selly Oak pointed to Russia's losses of 1,500 troops per day in Ukraine adding that the UK's Armed Forces could not sustain such a beating.

In a speech to the Royal United Services Insititute, Mr Carns warned: "In a war of scale – not a limited intervention, but one similar to Ukraine – our army for example on the current casualty rates would be expended – as part of a broader multinational coalition - in six months to a year."

The former full-time Royal Marine colonel pointed out that Russia would soon be moving onto its third army in Ukraine.

He added: "That doesn’t mean we need a bigger army, but it does mean you need to generate depth and mass rapidly in the event of a crisis.

"The reserves are critical, absolutely central, to that process.

"Without them we cannot generate mass, we cannot meet the plethora of defence tasks."

Mr Carns, the Labour MP for Birmingham Selly Oak, is not the only politician to voice concerns about the British Army's warfighting capability in recent months.

Ben Wallace, then Defence Secretary, highlighted a gap between the UK’s defence ambitions and its resources, suggesting the Army was facing delays in delivering essential modernisation programmes, such as the Ajax armoured vehicle projec.

He also questioned whether current spending would allow for effective participation in NATO operations​.

Meanwhile Lord Richard Dannatt, the former Chief of the General Staff, has criticised the British Army’s insufficient force structure to meet NATO commitments, calling for immediate steps to rebuild its combat effectiveness.

He suggested the Army might struggle to deploy and sustain a single division in high-intensity conflict.

Admiral Sir Tony Radakin, the current Chief of Defence Staff, acknowledged challenges faced by the Army while maintaining that current reforms and budget increases would address some of the capability gaps over time.

He supported modernisation efforts but admitted that progress has been slower than ideal.

Mr Carns was speaking on the day Foreign Secretary David Lammy pressed Nato to increase military support for Ukraine as he meets allies in Brussels this morning.

He also call for the allaince to deter co-operation between Moscow and other countries following the deployment of 10,000 North Korea troops to assist Russia's invasion of Ukraine.

Speaking ahead of his first Nato Foreign Ministerial Meeting, Mr Lammy said: "Investment in Ukraine's security is investment in Euro-Atlantic and global security.

"Ninety-nine per cent of military support to Ukraine has been from Nato allies.

"This support is critical to enabling Ukraine to defend itself against Russian aggression, and the UK and allies must double down on our efforts to ensure Ukraine prevails."