DAVID Cameron has been warned by a senior Conservative not to use the timing of the key Westminster vote on Trident to “play party politics” as a Cabinet split emerged over whether to hold it in March or October.

Some Conservative colleagues want the Prime Minister to delay the vote to the autumn so that Labour divisions are displayed openly at its party conference in September with the possibility of frontbench resignations. But others want to "maximise" the political pain for Scottish Labour in the run-in to the spring Holyrood elections by holding the vote to renew the Faslane submarine fleet next month.

At Commons question-time, Julian Lewis, who chairs the parliamentary Defence Committee, noted how Chris Grayling, the Commons Leader, had poked fun at a suggestion by Jeremy Corbyn that the nuclear subs could have their weapons removed and used as troop carriers; Mr Grayling branded the idea “madcap”.

But Mr Lewis told him: “It's one thing for you to poke fun at the Leader of the Opposition over his strange ideas on Trident's successor, as you did today, it's quite another for No 10 to adopt this policy on the question of delaying the vote, which everybody - from the MoD, industry and both sides of the nuclear debate in Parliament - expected to be taking place in the next few weeks.

"Can you look the House in the eye and tell us that No 10 is not playing party politics with the nuclear deterrent because, if they are, it is beneath contempt?" asked the Hampshire MP.

Mr Grayling replied that he, like Mr Lewis, supported the nuclear deterrent but could only tell his colleague that Trident would be debated “in due course”.

Recently, one senior Tory source stressed the Prime Minister had yet to make a decision on timing but said: "Ruth Davidson's preference is for an early vote but this is not a demand. Clearly, one consideration is the impact on Labour and what can give us maximum impact."

The Tory hierarchy is said by senior party sources to be divided on when to call the crunch Commons vote but it is believed Michael Fallon, the Defence Secretary, is pushing for it to take place before the Easter recess, which begins on March 24.

An early vote would mean that Mr Corbyn, as leader, would have to decide what policy line Labour would take as his party’s defence review is not expected to report until the summer. Given the deep divisions within Labour over Trident, it is possible that, as with airstrikes on Syria, he will have to concede to a free vote.

Meantime, writing in the House Magazine, Lord West, the former head of the Royal Navy and an ex-Security Minister in Gordon Brown’s government, branded Mr Corbyn's suggestion that the UK could deploy Trident submarines without nuclear weapons "dangerous and nonsensical".

The peer warned it would be "foolhardy" for the UK to abandon its deterrent in an "extremely chaotic" world and said claims that Trident could be scrapped to save money were "delusional".

He argued: "The case for maintenance of our minimum credible deterrent by replacement of the ageing Vanguard class submarines is so self-evident that I expect the Labour Party to keep its manifesto commitment.”

Noting how it was difficult to predict whether or not some countries might be prepared to use nuclear weapons, he said that it would be “foolhardy for any British government of whatever hue to make us vulnerable to possible threats by giving up the power to retaliate”.

Turning to Mr Corbyn’s suggestion, the ex-Navy chief said: "Having a Vanguard successor with missiles but no warheads fitted is dangerous and nonsensical. It would escalate tension dramatically, risk safe deployment and could result in a pre-emptive strike before the weapons are ready to fire."

He added: "The cries from a few military figures that dropping the deterrent will release funds for conventional forces is delusional and clearly those involved do not understand Whitehall. Indeed, no great sums would be released at all and in the early years there will be increased expenditure because of decommissioning."