The Astute class of submarines based at Faslane on the Clyde has seen reported reactor incidents at sea or on shore almost double from 12 in 2014 to 21 in 2015. Though the MoD insists that the incidents are all minor, critics warn that they undermine the boats’ reliability and safety.
The first submarine of the class, HMS Astute, has already been out on operations, and the second, HMS Ambush, was launched in 2011. The third, HMS Artful, was formally handed over the Royal Navy in December 2015.
The four remaining Astute submarines are either still being built by the defence firm BAE Systems at its Barrow shipyard, or are due to be built there. The construction programme has been subject to a series of delays and cost overruns.
The MoD revealed the number of safety events recorded with Astute submarine reactors between January 2012 and January 2016 in response to a request under freedom of information law. There were an average of more than 17 a year, or one every three weeks (see table below).