Movements of the United Kingdom's nuclear warhead arsenal continue at a baseline level and suggest that decommissioning of warheads from the Trident warhead stockpile is slowly taking place, according to an annual summary of warhead convoy movements for the year 2013 published by the Nukewatch network (available to download at the bottom of this article).
Evidence from convoy movements observed by Nukewatch is consistent with a programme for decommissioning around three warheads per year between 2011 and 2025 to bring the UK's total warhead stockpile down from around 225 warheads to around 180 warheads, as the government committed to do in the 2010 Strategic Defence and Security Review.
However, Nukewatch stresses that sustained monitoring over future years will be necessary to confirm this.
Nukewatch is a network of individuals which monitors the UK's nuclear weapons programme by observing the road transport of nuclear weapons, and has been watching and tracking warhead convoys for over 25 years.
The group considers that during 2013 at least two 'live' warhead convoys travelled between the Coulport nuclear arms depot in Scotland and the Atomic Weapons Establishment (AWE) at Burghfield in Berkshire, most likely dispatching four warheads to AWE for maintenance, surveillance, or decommissioning, and returning two warheads to Coulport.
Britain's nuclear warheads are moved on a regular cycle between the Atomic Weapons Establishment (AWE) in the South of England, where the UK's nuclear weapons are manufactured and maintained, and the Royal Naval Armaments Depot at Coulport, where warheads are stored prior to deployment on Britain's Trident submarines. By observing this cycle, it is possible to draw inferences about the level of activity of the UK's nuclear weapons programme
Nukewatch reports that the overall picture of convoy movements during the year represents a slightly lower level of activity than over the last year, but is consistent with a minimum baseline level observed over the past few years. During the 1990s and early 2000s warheads were transported across the country on a far more regular basis as the Trident programme was implemented and older warheads were returned to AWE for decommissioning.
As well as 'live' convoy movements, Nukewatch notes that convoy exercises and training activities also took place during 2013, and a number of special nuclear materials convoys were observed.