Campaigners yesterday spoke of their "delight" after winning a 70-year battle against the Ministry of Defence to release confidential documents relating to the sinking of a Second World War aircraft carrier.

A staggering 379 navy personnel died when HMS Dasher exploded in the Firth of Clyde, between Ardrossan and Arran, in North Ayrshire, in March 1943 with no German bombers in sight.

Nearly 70 years later the seven remaining survivors and hundreds of families of the dead still do not know exactly what happened to cause the vessel to explode and then sink.

However, yesterday, the MoD finally agreed to release a score of documents – called "casualty packs" – relating to the sinking.

Author John Steele, 72, has spent more than two decades trying to solve the mystery and find out what happened to the scores of bodies that were washed up at Ardrossan in the wake of the incident.

He said: "I'm absolutely delighted that these documents are being released."

Mr Steele received a letter from Andrew Robathan, Minister for Defence Personnel, Welfare & Veterans, last year stating that the MoD were considering waiting until 2044, when most survivors and families were dead, to release the casualty packs.

The author believes at least 26 of Dasher's navy crew were callously dumped in a mass grave in Ardrossan Cemetery.

Mr Steele added: "This disaster was self-inflicted, preventable and foresee-able. The Navy knew Dasher was a floating bomb and the least spark was going to cause a disaster."