One in six defence jobs could be axed if the Government presses ahead with cuts of 26 per cent to the industry's budget, according to a new report.
An analysis of the defence industry by Oxford Economics showed that cuts on such a scale would lead to a potential loss of more than 55,000 skilled manufacturing jobs.
Unite said the study showed that the spending cuts would "wreck" the UK's defence manufacturing industry, adding that the work tended to be concentrated in economically deprived regions of the country where other jobs were hard to find.
Bernie Hamilton, Unite's national officer for defence, said: "The Tory-led coalition wants to raze the UK defence industry to the ground. They believe wrecking the UK's sovereignty to manufacture defence equipment is a price worth paying.
"Tens of thousands of job cuts in some of Britain's most deprived regions will have tragic consequences. These skilled manufacturing jobs won't get replaced.
"As the Conservative party conference gets under way, Tories should get used to the fact that their party is no longer the party which can claim to be strong on defence. Instead, they are the party which plans to cripple Britain."
Speculation about the scale of defence cuts is rife after the Government launched a review, which is due to report back soon.
Unite said more than 300,000 jobs depended on the defence industry, adding that large numbers of workers will be made redundant if speculation about cuts of more than 20 per cent is confirmed.
Defence will be debated at the Conservative's annual conference in Birmingham later this week.