What is ‘Trident Replacement’ and what role does Parliament play? 

‘Trident Replacement’ refers to the UK’s programme to replace its  nuclear weapons system, ‘Trident’, with a new, like-for-like equivalent.  For more information on Trident and what its replacement means, you can view our useful Trident  Q&A briefing. 

Given that the replacement of Trident is a UK Government programme, it requires the consent of elected Members of Parliament to sign off on its delivery. The programme is also subject to Parliamentary scrutiny, and MPs have the right to question and query the Government on how the programme is progressing and on the range of monetary, safety, and security implications it brings to the fore, something that members of Parliamentary CND do on an ongoing basis.

Unfortunately, in 2016 a majority of MPs voted to replace the UK’s 4 Trident nuclear submarines, known as the ‘Vanguard-Class’, with a new class of submarines known as the ‘Dreadnought-Class’.

Whilst MPs have agreed to the programme of Trident replacement, they can, at any time, agree to vote to scrap this endeavour: this is what Parliamentary CND is campaigning for.  In the meantime, Parliamentary CND tasks itself to hold the Government to account on the Trident replacement programme, its costs, safety, and strategic relevance.

Trident replacement parliamentary timeline: Significant Parliamentary Debates and Reports

The intention to replace the Vanguard submarines for the Trident nuclear weapon system was formally announced in a Defence White Paper published in December 2006.

In response, CND published our own Alternative White Paper.

A House of Commons debate and vote in March 2007, by 409 votes in favour to 161 against, gave authorisation for initial research to begin.

In May 2010, the new Coalition Government announced it would continue with research plans to allow Trident replacement to go ahead, but that the Liberal Democrats could continue to argue for alternatives to ‘like-for-like replacement.’

In October 2010 the National Security Strategy identified state-on-state nuclear conflict as of ‘low likelihood’ but the accompanying Strategic Defence and Security Review announced research for Trident replacement would go ahead, with a final decision to authorise submarine construction in 2016.

In May 2011 a Parliamentary report (entitled the ‘Initial Gate’) and Ministerial statement updating MPs on replacement submarine research work announced key decisions on the adoption of a new nuclear reactor design to propel the replacement submarines, following which a new phase of detailed design work began.

At the same time an announcement was made that the Cabinet Office would conduct a review of alternatives to ‘like-for-like’ replacement to facilitate  Liberal Democrats making the case for alternatives. This was eventually published in July 2013.

In response, CND published a ‘Real Alternatives Review’ which looked at the option of non-replacement and disarmament, excluded from the Cabinet Office review. 

Since the May 2011, ‘Initial Gate’ paper, annual Parliamentary reports into the progress of the Trident replacement programme have since been published in December 2012 and 2013.

Following the 2015 General Election the UK Government undertook a Strategic Defence and Security Review, which announced that the cost of replacing the four Trident submarines would increase to £41bn. This was accompanied by the National Security Strategy, which confirmed the reduced threat level of states using nuclear weapons.

Despite the National Security Strategy confirming that nuclear weapons were no longer a ‘Tier One’ threat, the UK Government, now with a new Prime Minister in Theresa May, continued with their plans to replace the four Trident submarines and a debate and vote on the like-for-like replacement took place in 2016.

MPs backed Trident replacement by 472 votes to 117.