The UK will not be ready to fight an all-out war unless the Government addresses the Armed Forces’ capability and stockpile shortages and recruitment crisis, MPs have warned.

The Commons Defence Committee said the military is “consistently overstretched”, with the demands of operations personnel are deployed on leaving little time for training in warfighting.

“The Government risks being unable to build true warfighting and strategic readiness because of the sheer pace of operations, which could threaten the security of the UK,” the report said.

The panel suggested the “unrelenting pressure” on personnel has exacerbated the crisis in the recruitment and retention of both regulars and reservists, with more people leaving the Armed Forces than joining.

Efforts by the Ministry of Defence (MoD) to tackle the problem are not “being carried out at the required pace”, the report said.

The MPs urged ministers to ensure that the forces are not deprived of the time, resources and training they need to fight and win a high-intensity prolonged war.

Readiness “is essential to effective deterrence to our adversaries” at a time of heightened geopolitical instability, they said.

The committee’s inquiry heard that the “hollowing out” of the Armed Forces since 2010 had undermined the UK’s warfighting resilience, and that their reduction in size meant they would exhaust their capabilities “after the first couple of months of the engagement” in a peer-on-peer war.

It comes after Defence Secretary Grant Shapps last month said the world is “moving from a post-war to pre-war world” and the UK must ensure its “entire defence ecosystem is ready” to defend its homeland.

He insisted the size of the Army will not dip below 73,000 under the Conservatives, amid growing concerns about further cuts to troop numbers.

Sir Jeremy Quin, who recently took over as Defence Committee chairman, said: “A steady, continuous drip of operations and ongoing commitments has meant the military is unable to devote sufficient training and resources to high-intensity warfighting.

“While able to deploy at short notice and to fulfil commitments, our inquiry found that readiness for all-out, prolonged war has received insufficient attention and needs intense ongoing focus.

“On top of this, the high tempo of operations and unrelenting pressure on our Services has led to a drop in retention, compounded by a period of low recruitment and difficulties introducing and maintaining capabilities, thereby creating a vicious cycle.”

He said the Government must “either invest fully in our military or recognise that proper prioritisation of warfighting will mean less availability for other tasks”.

“We need to be strategic about the resources we have, including how to maintain and replenish stockpiles, and consider how to ensure that equipment – even after retirement – does not go to waste.”

The committee also complained that its inquiry was “hampered” by a “lack of Government transparency” and the “unacceptably slow” response to its requests for information.

Some 20,000 UK service personnel will take part in Nato Exercise Steadfast Defender across Europe, the alliance’s biggest such exercise since the end of the Cold War.

The MoD has been contacted for comment.