FOI release sheds new light on nuclear missile submarine collision

New information has emerged about an underwater collision which took place between a British and a French nuclear weapons submarine in the Atlantic Ocean in 2009.

Following a request under the Freedom of Information Act, excerpts from the inquiry report and briefings to Ministers about the incident have been released to Nuclear Information Service (available to download at the bottom of this page).  It is understood that the the decision to release even a limited amount of information about the incident was taken at the most senior levels in the Royal Navy following pressure from the Information Commissioner.

Full details of the circumstances of the collision remain shrouded in mystery, but Ministers were advised to take a “consistent and robust” approach that it was “an unfortunate and highly unlikely accident” following a Ministry of Defence investigation into the incident which concluded that “at no time was nuclear safety compromised”.  

The collision between HMS Vanguard and FNS Le Triomphant took place in the Atlantic Ocean in early February – although precise details of the date and location of the accident have not been revealed.  News reports at the time of the collision stated that it took place in heavy seas in the Eastern Atlantic, in the middle of the night between February 3 and 4 2009.

The Ministry of Defence has never fully explained what happened during the collision.  The then Defence Minister, Bob Ainsworth, told Labour MP Harry Cohen in March 2010 that he was withholding “all particulars” of the collision from release on grounds of national security following a request to publish a summary of the report on the collision.

The information released under the FOI Act includes excerpts from a briefing to Ministers dated 17 February 2009 – the day after reports of the collision appeared in newspapers – which noted “that HMS Vanguard and her crew are safe and no damage to nuclear weapons or propulsion plant occurred” and “that Continuous At Sea Deterrence was not broken and is being maintained.”  Ministers were assured that an investigation with “a full review of decision making at all levels” would be rapidly undertaken to establish the causes of the incident.

The papers reveal that a press line was agreed by Ministers and shared with the French government,  stating that the two submarines “were conducting routine national patrols in the Atlantic Ocean” and “came into contact at low speed”, but that there had been ”no compromise to nuclear safety”.

A further briefing to Ministers dated 23 March reported that a “comprehensive analysis” of the circumstances surrounding the collision had now been completed, and confirmed that “nuclear propulsion and weapon safety was not compromised during this incident … the shock received and logged by the Strategic Weapon System were within normal tolerable limits.”  Ministers were advised that, “as a department, we should be consistent and robust that this was an unfortunate and highly unlikely accident involving two vessels operating totally independently as they conducted national deterrent patrols.”

The investigation into the incident took evidence from the submarine's crew and Commanding Officer as well as reviewing signal logs, records of the incident, and 'black box' type computer data from the submarine which was analysed by the Ministry of Defence Strategic System Performance Assessment and Analysis Group (SSPAG) and the Military Data Analysis Group.

The SSPAG – which routinely analyses data following every Trident submarine patrol – was specially augmented with a submarine command experienced Captain and Commander to undertake the investigation.

Although no information about the circumstances of the collision has been revealed, the report noted that Vanguard undertook the “standard package” of pre-patrol onshore and at-sea training and “achieved the required standards” before setting out on patrol.  Planning for the patrol were “well considered and comprehensive”.

Media speculation at the time of the collision discussed the apparent failure of each submarine to detect the other, despite carrying state-of-the art technology for detecting other vessels.  However, following training Vanguard's Sound Room sonar team were described by the assessor as “the strongest of operators he had seen”.  The team “performed well at sea and were assessed as Very Satisfactory”

Following the collision a secondary shield survey, a reactor core integrity check and missile testing were undertaken, confirming that “both the Reactor and Strategic Weapons were safe and that no compromise to nuclear safety had occurred”.

The report concludes: “At no time was nuclear safety compromised and the Strategic Weapon System remained inside tolerable limits at all times”.  The assessment team made “a number of recommendations” associated with the incident – including high level policy recommendations.

No information about these recommendations has been released to date, but at the strategic level it is believed that the incident has been reviewed by the Franco-British Joint Nuclear Commission, which was established 1992 and meets regularly to allow discussion of nuclear policies and doctrines between senior civil servants.  There has been speculation that, following the incident, efforts have been made to include the French Navy in 'water space management' arrangements between the Royal Navy and the US Navy which are aimed at preventing submarine collisions.

Following the incident the submarine commander, Richard Lindsey, was awarded the Queen's Commendation for Valuable Service for “exceptional service in difficult circumstances” – suggesting that the response to the incident on board HMS Vanguard and the return voyage to the Faslane submarine base, which may have taken up to ten days, were far from straightforward operations.


Timeline of events:

3-4 February 2009:

Collision reportedly takes place in the Eastern Atlantic


6 Feb:

French Ministry of Defence reports that Triomphant had collided with an “immersed object (probably a container)” according to the BBC.


14 February:

HMS Vanguard arrives at HMNB Clyde according to Ministry of Defence.

Scottish CND reports that the submarine berths at the Coulport Explosives Handling Jetty.


16 February:

Daily Telegraph reports that collision took place.

First Sea Lord Admiral Sir Jonathon Band states that the submarines came into contact at low speed and no injuries were reported.


17 February:

Briefing to Ministers.


20 February:

HMS Vanguard videoed by Scottish CND entering Faslane shiplift for repairs under cover of darkness.


27 February:

Investigation report complete.


23 March:

Further briefing to ministers.


1 April:

Vanguard leaves the shiplift to berth at the Faslane Finger Jetty.


10 June:

Defence Minister Bob Ainsworth says in a written answer to Parliament that HMS Vanguard is now operational again.


11 September:

Commander Richard Lindsey (Captain of HMS Vanguard) awarded the Queen's Commendation for Valuable Service for “courage and high quality leadership in early 2009”.


27 Feb 2013:

MoD release limited info about the collision in response to a FOIA request.



Download the papers on the collision which were released under the Freedom of Information Act here:


Related content

By continuing to use the site, you agree to the use of cookies. More information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.