Labour can't renew Trident - Fallon
Defence Secretary Michael Fallon has refused to confirm the Conservatives would vote with a minority Labour government to renew Trident.
After his opposite number Vernon Coaker affirmed Labour's commitment to maintaining the nuclear deterrent, Mr Fallon asked how this could be achieved when the SNP - predicted to hold the balance of power after May 7 - was so set against it.
He told the BBC Daily Politics election debate on defence and security: "How can you get renewal of Trident if you are a minority Labour government? You can't get power on your own, you are being propped up by the SNP.
"How can you possibly get it through? When Nicola Sturgeon has said it's an absolute red line."
Mr Coaker insisted Labour would not negotiate on the country's national security, before asking him: "How would the Conservatives vote?"
Mr Fallon replied: "You want to leave it to the uncertainty of a 10 o'clock vote, not knowing which MPs are going to vote which way?
"This is too important to be left to a late-night vote in the House of Commons."
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."
Presenter Andrew Neil asked: "Would you not support a Labour government that was going to renew Trident?"
The defence secretary replied: " Our aim in this election is to have a majority Conservative government where you don't have that question.
"Because you can avoid that question ... We are not planning to lose the election ... the country needs to avoid that question by the certainty of a Conservative government that is absolutely committed. We can't have this confusion or uncertainty."
Trident is a system of submarine-based nuclear missiles, based on four boats. At any time at least one of them is at sea, on patrol, somewhere in the world. One of the four Vanguard-class submarines has been constantly on patrol since the system came online in 1994.
It is operated by the Royal Navy and based at the Clyde Naval Base on the west coast of Scotland. The name Trident comes from the American-built UGM-133 Trident II missiles which are carried by the boats.
While the missiles are expected to be useful for several more decades, the four submarines are coming to the end their life. The Vanguard-class was designed to operate for 25 years - taking the boats to the mid 2020s.
The life of the submarines can be extended by about five years with a refit but new submarines - either new Vanguard-class boats or a completely new design - will be needed to renew the Trident system.
A House of Commons Library note suggests that in 2013/14 prices, replacement for the whole Trident system would cost about £17.5 billion to £23.4 billion. Replacing the submarines would be £12.9 billion to £16.4 billion of that cost. Trident opponents, such as the CND, claim replacing the system will cost £100 billion over its lifetime.
The SNP, Greens and Plaid Cymru are in favour of scrapping Trident, in contrast to the Labour and Conservative position.
Ms Sturgeon has said that halting its renewal would be her top priority in a hung parliament, arguing the money could and should be better spent.
At the urging of the Liberal Democrats, the Coalition commissioned a review of alternatives to a like-for-like replacement for the Trident system.
Produced by former Liberal Democrat defence minister Sir Nick Harvey, it suggested abandoning continuous at-sea patrols and cutting the number of submarines from four to three. Both the Conservatives and Labour rejected this as a "part time" deterrent which would risk increasing international tensions every time a sub was put to sea.