"This is a major blow to the agency," said Prospect national secretary Mike Clancy. "The decision to roll forward work on the Harrier platform from DARA to RAF main operating bases is a new and worrying development. We fear it will be the start of a wider series of cuts resulting from the MOD End to End review of the Air supply chain.

"We still await the overall outcome of the End to End review and this decision raises fears that there is more bad news to come. We will be pressing ministers for answers about the future for DARA and the strategic position it will occupy going forward. These job losses must be justified on efficiency grounds before they can be implemented."

Speaking at the annual conference of Prospect’s Ministry of Defence Group in London, which represents 18,000 professional staff, Clancy asked: "Can these cuts be justified on efficiency grounds, or are they just another example of MOD caving in to the Treasury’s cost-cutting agenda for the people and facilities that support our armed forces?"

Clancy criticised MOD’s "high-handed" failure to consult staff or unions before the announcement and said it was a betrayal of previous official promises and the successful track record of DARA since it was set up.

A conference motion from Prospect’s DARA branch called on the minister for the armed forces to justify his decision and to oppose job losses that are not supported by a reasoned business case. "Simply transferring work to a mixture of service personnel and contractors is unacceptable, arguably more expensive and casts a shadow over the whole MOD change programme," said the emergency motion, which was carried unanimously.

DARA was set up as a trading fund in 1999 and employs 3,800 staff. Its main site is at RAF St Athan in South Wales where a £70m investment to build a high-tech business park, known as Project Red Dragon, was approved last year. DARA has three other sites at RAF Sealand in North Wales, Almondbank near Perth in Scotland and Fleetlands near Portsmouth.