Technology giant Hewlett-Packard plans to cut more than 1,100 jobs at a number of UK sites in the new year, according to union leaders.
Unite said the US-based firm will axe 1,124 posts in Bracknell, Sheffield and Warrington, as well as among staff who work from home.
The union claimed the company was a "long-term addict to a culture of job cuts", adding that its European managers had little autonomy.
Unite said the company blamed falling demand and reorganisation for the job losses it wants to implement in the first three months of 2014.
Plans were being outlined at a meeting in Bracknell, Berkshire, today.
Unite national officer Ian Tonks said: "For the last five years HP has been addicted to a culture of job cuts in the UK to such an extent that its highly skilled workforce has little faith in the way the company is being managed and will be going forward.
"Unite will be doing everything possible to mitigate these job losses which are a hammer blow to the UK's IT sector and very distressing for employees in the run-up to Christmas."
Unite said 618 jobs could be lost at the Bracknell hub, although the employees work at multiple locations; 483 will go at Warrington and 23 at Sheffield.
"The proposed UK workforce management plan is part of HP's global multi-year productivity initiative that was announced on May 23, 2012, and updated at its securities analysts meeting on October 9, 2013, to address current market and business pressures in support of HP's turnaround.
"HP remains committed to supporting the employability of its employees through a number of internal initiatives, including re-skilling, redeployment and support to obtain alternative employment as appropriate."
Public and Commercial Services union general secretary Mark Serwotka said: "As well as being devastating for workers hearing this news in the run-up to Christmas, it is a body blow for local economies that need jobs and investment, not more cuts.
"Private companies with public sector contracts are taking their cues from the Government's damaging austerity policies, and putting profits before people's livelihoods."