Grant Shapps has said he is “working hard” to ensure the armed forces are not depleted, amid warnings that military personnel are leaving faster than they can be replaced.

The Defence Secretary stressed he was taking steps to ensure the UK has “the men and women we need for our armed forces”, as MPs debated the UK’s military action against Yemen-based Houthi rebels.

Ministers have in recent weeks highlighted rising tensions around the globe, with Mr Shapps warning of movements towards a “pre-war world”.

He was questioned about the UK’s preparedness for future wars as parliamentarians were granted the chance to speak about the two waves of air strikes against the Houthi militants in recent weeks.

The rebel group has been attacking container ships passing through the Red Sea since November, claiming the vessels are linked to Israel in the context of the conflict with Hamas.

The UK has disputed this, and Mr Shapps told MPs the attacks were a “global problem” and had put “at risk” the vital trade route linking Europe to Asia via the Suez Canal.

He claimed the second wave of air strikes in which the UK took part on Monday had further degraded the Houthis’ “ability to hold our seas to ransom”, and added: “We’re not aware that there were any civilian casualties and the operation was designed in that context.”

But Conservative former minister Mark Francois raised concerns about reports of a recruitment crisis within the armed forces, to prepare for threats against the UK as global risks escalate.

Mr Francois said: “I completely support the Government’s action, which is taken in accordance with international law and defending freedom of navigation on the high seas, but we can only do it with people, otherwise there is no-one to maintain the typhoons or to crew the warships.

“We now have people leaving three times as fast as we are recruiting, as the Secretary of State is aware.

“Can he give a commitment now he will come to the House before Easter to make a statement about what we are doing about retention of critical armed forces personnel? He knows why this is important.”

The Defence Secretary replied: “He will be pleased to know that I have recently been holding meetings with individuals who he believes himself will help to resolve this issue.

We demand the right to scrutinise the Government, we can only do that if we don’t vote on the wars

“I am working very hard to make sure that in common with actually many Western militaries, armed forces, that we do have the men and women we need for our armed forces, skilled up to the right levels and capable of taking on this challenge.”

Mr Francois’s recruitment warning came as General Sir Patrick Sanders, the outgoing Chief of the General Staff, said in a speech that Britain should “train and equip” a “citizen army” to ready the country for a potential land war with Russia.

Conservative MP Richard Drax (South Dorset) said: “Unfortunately the peace dividend has continued to take its toll, and the Royal Navy is critically short of ships and sailors, to the point we are endangering the security of our country.”

He said he wanted “no more arbitrary targets” on defence spending, saying instead the military should be asked what it needs to “play a prominent role in Nato and to defend our country and dependants”.

He said if more money was needed than the Government can afford, it should “raise the tax revenue by lowering taxes”, which he said would grow the economy and allow for more money to be spent on defence.

Elsewhere in the debate, senior Tory MP James Gray warned against demands that the Government hold a vote ahead of any future military action.

Liberal Democrat leader Sir Ed Davey was among MPs who had called for a vote on the RAF strikes, claiming it would lend the legitimacy of the Commons to the action.

But Mr Gray claimed a vote would “emasculate” the House of Commons and make it difficult for MPs to scrutinise the Government.

If we're taking military action, I want to take some responsibility as a member of this House and I want to be able to go back to my constituents and explain how I've exercised that responsibility, and that's why I believe we should have a vote

He said: “If we vote on something – it’s happened to the Labour Party over Iraq in 2003 – it then becomes extremely difficult to criticise the Government on what they’re subsequently doing.

“It’s right that we should scrutinise the Government, we should not vote on these matters. Have statements, have debates, have votes after deployment.

“The moment we allow ourselves to be forced into a whipped vote in front of deployment then we are by definition emasculating this House.

“It’s quite wrong from the point of view of defence, and it’s quite wrong from the point of view of parliamentary scrutiny.

“We demand the right to scrutinise the Government, we can only do that if we don’t vote on the wars.”

Labour former shadow chancellor John McDonnell meanwhile argued MPs should have a vote on the military action as he warned the Commons is “not taking its responsibilities seriously” given “we’re on the edge of real danger” in the Middle East.

He said: “If we’re taking military action, I want to take some responsibility as a member of this House and I want to be able to go back to my constituents and explain how I’ve exercised that responsibility, and that’s why I believe we should have a vote.”