"Labour Would Consider Cutting Number of Nuclear Submarines"
A Labour government would consider if one submarine fewer could be used to provide Britain's nuclear deterrent, according to shadow chancellor Ed Balls.
He said the party was committed to renewing Trident and providing a continuous at-sea deterrent.
The fleet of four Vanguard-class submarines which carry the Trident missiles are due to be replaced from 2028, with a final decision on whether to replace all four due to be taken in 2016 - after the 2015 election.
But Mr Balls said difficult questions need to be asked during the next defence review - including whether the job could be done with three boats.
Speaking on BBC Radio 5 Live's Pienaar's Politics, Mr Balls reiterated Labour's commitment to providing Trident while offering the greatest value for money.
Mr Balls said: "We will look to see if there are ways in which we can make savings in the procurement process.
"Of course, if I'm going to government I'm going to challenge the strategic defence review to answer that question in the toughest way - that if it turns out the only way strategically to deliver continuous at sea is four boats, then absolutely we will have four boats.
"But my job is to ask those questions and therefore we're going to challenge to see whether there's any way you could do it with three rather than four."
"I think many of the experts think in the end not, but it's a good thing for us to do, to ask the difficult questions."