LABOUR has insisted it still supports the retention of Britain's Trident nuclear deterrent after Jeremy Corbyn appeared to throw it into doubt.

The Labour leader said he would order an immediate strategic defence review covering "all aspects" of defence policy if he won the general election on June 8.

In a statement issued following his appearance on BBC1's The Andrew Marr Show, a party spokesman said: "The decision to renew Trident has been taken and Labour supports that."

In his interview, Mr Corbyn - a life-long supporter of unilateral nuclear disarmament - declined to say whether the party still backed Trident.

Asked whether it could be cancelled under Labour, he said: "We will have a strategic defence review immediately which will include all aspects of defence.

"We would then look at the situation at that time."

Pressed on whether it would be in Labour's election manifesto, he said: "We haven't completed work on the manifesto yet.

"We are having that discussion in the Labour Party and we will produce our manifesto early in May."

Mr Corbyn's comments threatened to reopen the bitter divisions within the party after he was forced last year to abandon his attempts to persuade it to back his unilateralist position in the face of opposition from the trade unions.

The Labour leader - who has previously said he would never authorise the use of nuclear weapons - said he stood by his past views on the subject.

"I have made clear my views on nuclear weapons. I have made clear there would be no first use of it. I have made clear that any use of it would be a disaster for the whole world," he said.

Asked what he would say in the "letters of last resort" written by prime ministers with their final instructions to the commanders of Britain's four Trident submarines, he said only: "A strict instruction - follow orders when given."

He was immediately accused by the Conservatives of preparing to "dismantle" Britain's defences.

Mr Corbyn faced further controversy when he suggested he would be reluctant to order a drone strike to take out the leader of Islamic State (IS) Abu Bakr al-Baghdadi if British intelligence discovered his whereabouts.

"What is the objective here? Is the objective to start more strikes which may kill many innocent people as has happened or is the objective to get a political solution in Syria? Approach it from that position," he said.

"I think the leader of Isis not being around would be helpful. I am no supporter or defender in any way whatsoever of Isis.

"But I would also argue that the bombing campaign has killed a large number of civilians who are virtually prisoners of Isis so you have got to think about these things."

The row came as the Tories made clear they intended to make Mr Corbyn's fitness for office a key issue in the election campaign.

In a highly personal attack, Conservative Party chairman Sir Patrick McLoughlin said the Labour leader was "not suitable" to be prime minister and would be unable to take the "difficult decisions" needed in the event of a major terrorist attack.

"There are decisions which prime ministers have to take and those people in authority have to take (which) are sometimes very uncomfortable," Sir Patrick told The Sunday Telegraph.

"If they don't take them, we're at danger ... I know that with Theresa May, she would take them. I'm not sure that Jeremy Corbyn would.

"The man is not suitable to become prime minister of this country. He has been a rebel without a cause in the Labour Party."

In his interview, Mr Corbyn suggested he could suspend RAF air strikes on IS in Syria and Iraq, and said he would urge US President Donald Trump to resume international peace talks on Syria in Geneva.

"I want us to say 'Listen, let's get people around the table quickly'. A way of achieving that - suspend the strikes? Possibly. The point has to be to bring about a political solution."

Mr Corbyn refused to be drawn on whether he would insist on the end of the free movement of labour with the European Union in the Brexit negotiations.

He said that Brexit would mean the end of free movement and that new arrangements would have to be agreed as part of the withdrawal negotiations.

"What I would insist on is trade access and see what follows from that. That has got to be the key point," he said.

"We then work out a system by those that are able to come here for work and so on as well as British people able to go to other parts of Europe to work."

Home Secretary Amber Rudd said: "This morning we learnt that Jeremy Corbyn would refuse to strike against terrorists, dismantle our nuclear defences and fail to control our borders,"she said.

"Unless people turn out and vote Conservative, this man could be our Prime Minister in less than seven weeks' time - propped up by the SNP and Lib Dems in a coalition of chaos."