Election 2015: Labour 'will renew four Trident subs'

Labour's shadow defence secretary Vernon Coaker has said his party is committed to renewing four Trident submarines if it wins the election.

Mr Coaker told the latest BBC Daily Politics debate that evidence said four nuclear-armed boats were needed.

In March, Ed Balls said the party would consider reducing the number to three.

Defence Secretary Michael Fallon, meanwhile, refused to say whether his party would back a Labour minority government on Trident renewal.

A decision on whether to replace all four Vanguard-class submarines, which carry the Trident missiles, is expected to be taken in 2016. They are due to be replaced from 2028.

Both men also declined to commit their parties to spending a minimum of 2% of the nation's wealth - measured by gross domestic product (GDP) - on defence, in line with Nato's target.

Spending 2% is not mandatory to Nato membership but BBC defence correspondent Jonathan Beale has said the UK's credibility would suffer in the eyes of the US if it failed to commit to that level of investment.

Policy guide: Where the parties stand

On Trident, Mr Coaker said his party's policy was "very clear and very simple".

"We are committed to renewing the deterrent, we are committed to a continuous at-sea deterrent and we will have four boats because that is what the evidence says that you need," he said.

Last month, Mr Balls said the party was committed to renewal but would "challenge" a strategic defence review to "see whether there's any way you could do it with three rather than four".

The party representatives were also quizzed on spending

Mr Fallon said Labour's policy was "all over the place".

But Mr Coaker replied: "It's quite clear and it's exactly as I've just stated it - the evidence says you need four boats so we'll have four boats."

Mr Coaker also said his party would not negotiate on the issue in the event of a hung Parliament.

Mr Fallon, asked by his counterpart how the Conservatives would vote if a Labour minority government tried to win support for new submarines in the Commons, said: "You want to leave our nuclear defence to the uncertainty of a 10 o'clock vote, not knowing which MPs are going to vote which way, cobbled together in some deal with the SNP."

'Absolute fortune'

Pressed to clarify why Labour could not count on the support of the Conservatives, he went on: "Because you'd have uncertainty. The way to be absolutely sure about our nuclear defence is to vote Conservative, have the four ballistic missile submarines."

The SNP's Angus Robertson said the nuclear deterrent "does not work".

He added: "The austerity parties are prepared to spend an absolute fortune on something by its very nature it can never be used. It will destroy the world."

Liberal Democrat defence spokesman Nick Harvey said his party did not believe the UK had a nuclear adversary at the moment, but that the capability to use nuclear weapons should be retained.

The Liberal Democrats favour cutting to three, saying the existing system was designed for the Cold War era.

Green spokesperson Rebecca Johnson said her party supports a "multilateral nuclear ban treaty".

Spending review

The candidates were also quizzed as to whether their parties would meet the Nato 2% target. Mr Fallon said the UK was meeting that figure now, but the sum for future years would be set out later.

He said: "The actual percentage for each of the next spending review years will be set in the autumn. We can't calculate now. We can't commit now to the exact totals for the three following years of the current year but we are already spending 2%."

Mr Coaker also said he would have to wait for a spending review.

He said: "We've committed to where the budget is now. That's the starting point. There is a comprehensive spending review. I'm not going to pre-empt that. What happens after it will be a matter for that spending review."

Mr Harvey said: "It's simply not possible. I can't see any way of finding the additional £6bn a year that will be needed in the last year of this parliament that will be matching the 2% commitment."