Relatives of two servicemen killed with 12 others when a Nimrod plane exploded mid-flight in Afghanistan have served a writ on Defence Secretary John Hutton.
Graham Knight, father of RAF Sergeant Benjamin Knight, 25, said the action has been taken for negligence, failure to minimise risk and breach of the right to life.
Barrister John Cooper, who is also representing the family of Flight Lieutenant Steven Swarbrick, 28, served a holding writ in September on the then Defence Secretary Des Browne.
The full form, submitted against Mr Hutton, had to be served before January 2.
Sergeant Knight and Flight Lieutenant Swarbrick were killed with a dozen other servicemen when the Nimrod spy plane exploded minutes after undergoing air-to-air refuelling on September 2 2006.
If the action is successful it could pave the way for other families to sue the Government over the death of loved ones in Iraq or Afghanistan.
It is also the first time the Ministry of Defence has faced legal action under the European Convention on Human Rights, a move Mr Cooper called "groundbreaking".
The action has officially been taken by the two men's mothers Trish Knight and Pam Swarbrick.
Charles Haddon-Cave QC is leading a review into the "broader issues" surrounding the crash which is due to be completed in the first quarter of next year.
