The MoD have released pictures of the successful launch of an unarmed Trident ballistic missile by HMS Vigilant during a test launch in the Atlantic Ocean last week.
Nick Clegg accused Defence Secretary Philip Hammond of "jumping the gun" on Trident, as coalition tensions grow over the future generation of British nuclear-armed submarines.
The Deputy Prime Minister dismissed suggestions that an additional £350 million of funding announced for designing a replacement deterrent "made clear" the Government's commitment to maintaining the system.
Mr Clegg insisted the coalition agreement will not be "undermined or contradicted" and the Liberal Democrats' review into alternatives will continue.
Having seen the papers this morning, I think some people are jumping the gun on this Trident decision.
The coalition agreement is crystal clear - it will not be changed, it will not be undermined, it will not be contradicted.
The final decision on Trident replacement will not be taken until 2016, however much other people may not like it that way.
A senior Liberal Democrat source said:
There has been no change in policy on Trident. This is just some detail around the announcement of funding that was made back in May 2011.
The crucial decision on maingate and whether there will be a like-for-like replacement for Trident will not be made until 2016.
The Liberal Democrats will continue to make the case for alternatives to a like-for-like replacement. Our current review into those alternatives will report next year.
The announcement followed the successful firing of an unarmed Trident ballistic missile by HMS Vigilant during a test launch in the Atlantic Ocean last week, according to the the MoD.
HMS Vigilant is one of four Vanguard Class submarines which maintain the UK's nuclear deterrent.
The Vanguard submarines will be replaced from 2028 by the Successor which is currently being designed by British companies.
As a result of this latest announcement, BAE Systems will proceed with an additional £315 million worth of work, with a further £38 million carried out by engineering support services company Babcock
– Philip Hammond MP, Defence Secretary
Our continuous submarine-based nuclear deterrent is the ultimate safeguard of our national security and the Government is committed to maintaining it, both now and in the future.
The test firing and further investment in replacing the deterrent demonstrates that commitment. This latest expenditure for the next generation of nuclear-armed submarines is an investment in UK security and the British economy, sustaining high-quality jobs and vital skills.
Defence Secretary Philip Hammond is expected to announce an additional £350 million-worth of funding for the next stage of designing the future generation of British nuclear-armed submarines.
The Ministry of Defence said that the investment will sustain 1,200 UK jobs and follows the initial £350 million of design work announced earlier this year.