Thousands more civilian jobs are to be axed in the Ministry of Defence after a miscalculation on staffing cuts, according to union leaders.
Prospect warned that the MoD was "heading for the cliff edge" over cuts after being told that another 3,000 posts would be axed on top of 25,000 previously announced losses.
The union warned that the job cuts were being "rushed through" and "mismanaged" under plans to save money.
National officer Steve Jary said: "MoD is driving off a cliff, looking over its shoulder at a pack baying for civil service blood. Our members have had enough. Morale could not be lower.
"It is cutting the very people it needs to maintain its role as an intelligent customer and to provide support to our hard-pressed armed forces. It just doesn't make sense. The armed forces needs both the skills and specialisms of those in the civil service coupled with the military capacity provided by our soldiers."
The recent strategic defence and security review (SDSR) included plans to cut 25,000 civilian jobs from the MoD before 2015, but union officials said that figure was now 28,000.
The 3,000 extra job losses by 2015 are being brought forward from among 7,000 it was announced in July would be axed between 2015-2020.
The job losses are hitting admin staff as well as engineers and maintenance workers and are three times as severe as cuts to the military, said Prospect. By 2015 there will be 55,000 civilian staff in the MoD, compared with 118,000 in 1997, said the union.
A MoD spokesman said: "Each year, we review our plans to take account of changes over the previous 12 months and to ensure that we have the right equipment and manning levels to meet the future needs of our armed forces as agreed in the strategic defence and security review.
"Final decisions have yet to be taken but this annual process rightly considers the status of all our key programmes to ensure the continued coherence and balance of the whole programme."