A tank explosion which killed two British Army soldiers was caused by a design flaw, a coroner has found.

Royal Tank Regiment corporals Matthew Hatfield, 27, and Darren Neilson, 31, died during a live firing exercise at Castlemartin Range in Pembrokeshire.

A seal stopping explosive gases escaping into a tank crew’s turret was not in place before the lethal blast. The manufacturer failed to spot the tank’s gun could fire without the key safety component.

Cpl Neilson, 31, from Preston, Lancashire, was the tank commander and was thrown from the turret in the blast on 14 June 2017.

Cpl Hatfield, 27, and a father of one, from Amesbury, Wiltshire, was loading ammunition. Both men were taken to hospital but died of their injuries the following day.

Two other soldiers, Warrant Officer Stuart Lawson and Trooper Michael Warren, were also injured but survived. The airtight seal, a bolt vent axial (BVA), that would have prevented explosive gases being released into the tank’s turret was not in place when the men fired on 14 June 2017.

Senior coroner for Birmingham and Solihull Louise Hunt said the «hazard» had not been adequately tested by BAE and the Ministry of Defence in manufacture. Ms Hunt also identified other factors which contributed towards the two deaths. There was no written process to check the presence of the airtight seal and the soldiers were unaware it had been removed on a prior exercise.

Ms Hunt said: «The main cause of this incident was the tank being able to fire without the BVA assembly being present. «During production and manufacture of the gun, this hazard was not adequately considered or investigated and therefore the ability of the gun to fire without the BVA present went undetected.»