Armed forces minister Nick Harvey today gave a strong hint that the final decision on the like-for-like replacement of Trident would take place after the 2015 general election.
The "main gate" decision on the nuclear deterrent - the "point of no return" - is currently scheduled for the end of 2014 or the start of 2015, he said.
Mr Harvey told the Liberal Democrat conference: "If it were to be delayed until just after the May 2015 election, it is of no great financial significance, it is of no great military significance, it is of no great industrial significance.
"But believe me, it is of profound political significance.
"Conservatives know that they are not going to be able to look to the Liberal Democrats to get that through Parliament, so the issue will be a hot potato for Labour."
Lib Dem members in Liverpool voted unanimously for a policy motion calling on ministers to allow a full review of alternatives to the like-for-like replacement of Trident to be included in the Government's Strategic Defence and Security Review (SDSR).
Mr Harvey supported the motion, describing it as a "very useful restatement of our policy on this issue".
Lib Dems believe the UK should not commit itself to "another Cold War-scale nuclear deterrent and take up that stance for another 40 years", he said.
"We are of course in a coalition, and in a coalition we get some of what we want and they get some of what they want.
"And Trident is one of the few issues which is written into the coalition agreement as one which is acknowledged that the two parties have different views.
"And the coalition agreement provides that the Liberal Democrats will continue to argue the case for alternatives - and believe me, that is exactly what I'm going to do."
Mr Harvey said that if the main gate decision was delayed until May 2015, Labour would have the "headache of deciding whether they are going to ride to the rescue of the Conservative Party on Trident".
He added: "The Liberal Democrats are not going to change our mind.
"As for Labour, watch this space. This story ain't over yet, it's going to run and run."
Party grandee Baroness Williams of Crosby said Trident was a "Cold War weapon".
"We've moved on from the Cold War and we should think a bit more about what we want to do in the world," she said.
Defence Secretary Liam Fox had spoken of the "special relationship" with the US, she said.
"Mr Fox, have you noticed that the American people did elect a new president and that Mr Bush is no longer the president of the United States?" she said to applause.
"President Obama is doing everything in his power to move multilateral disarmament forward.
"Right now the US Senate is considering whether or not to ratify the first major disarmament agreement in the last 10 years.
"And that ratification hangs by a thread. Would it not be ludicrous if the UK moved in the direction of like-for-like replacement to last for the next 40 years, locking our children and grandchildren into the position?"
Lib Dem senior peer Lord Roberts of Llandudno spoke of the "moral lead" the UK should take on the issue of nuclear weapons.
He told the conference Britain could not justify a like-for-like replacement "when we're telling other nations in the world not to do this".
"Where is our moral lead? Where is our moral argument? Who are we?"
The motion was chosen for an emergency debate following a ballot of delegates earlier this week.
Moved by MP Julian Huppert, the motion calls on Lib Dem ministers to "press for the extension of the SDSR to allow a full review of the alternatives to like-for-like replacement of Trident".
It also urges them to "ensure the SDSR considers cost-saving options such as ending continuous at-sea patrols and extending the life of Vanguard submarines".
And it says the review should "make explicit the opportunity cost of Trident replacement".
Chancellor George Osborne has said the cost of the like-for-like replacement of Trident - likely to be £20-30 billion - would have to come from the Ministry of Defence's budget, rather than directly from the Treasury.
Liberal Democrats are worried this will result in "severe restrictions" in Britain's military operations.
Opening the debate, Mr Huppert argued that Trident should be part of the SDSR: "I say to the Tories: there's nothing to worry about.
"If it turns out that Trident is essential, it'll pass the review with flying colours. And if it isn't essential, then it really must be reviewed."
Kate Hudson, general secretary of the Campaign for Nuclear Disarmament (CND), welcomed the debate and vote.
"The Liberal Democrats have strongly reasserted their policy on Trident and it is now clear that they will pursue those goals," she said.
"The coalition agreement enshrined the fact that there are differences between the two Government parties on Trident, but this conference has made clear that Liberal Democrat principles will not be swept aside and they will make full use of their right to pose alternatives to Trident replacement, up to and including disarmament.
"We now hope that Lib Dem ministers will vigorously pursue the outcome of this motion to ensure Trident is indeed included in the Strategic Defence and Security Review.
"As many speakers observed, not only is Trident a Cold War weapon that needs to be strategically reconsidered, it also carries a massive opportunity cost in defence and other areas of public spending."
Labour MP John Woodcock, in whose constituency of Barrow and Furness the replacement Trident submarines would be built, said: "New Lib Dem defence minister Nick Harvey is brazenly admitting to playing politics with Britain's national security - that is the height of irresponsibility from the new Government.
"Last week Mr Harvey reassured his new friends in the House of Commons that he 'wasn't aware of any suggestion to delay decisions on Trident' and said the timetable had been decided.
"But he has immediately reverted to type in front of his supporters and said the Government may delay decisions on Trident purely for political reasons.
"That shows the lack of principle at the heart of the new Government and highlights the risk to the British people that this mix of Conservatives and Liberal Democrats represents."
Shadow defence secretary Bob Ainsworth said: "This is a completely immature way to decide our future defence and security policy.
"The Government must make those decisions in the best interests of our country, not delay them just to score political points.
"Putting off difficult decisions shows just how weak this coalition is.
"The Liberal Democrats need to grow up and start acting like a responsible governing party."Reuse content