Anglo-Swedish drugs maker AstraZeneca has announced a further 7,300 job cuts over the next two years as part of a new restructuring programme.
The GMB Union has said 250 to 300 of the cuts will be in R&D at the firm's site at Alderley Park, Cheshire.
It also said there would be unspecified back office cuts at other UK sites.
AstraZeneca announced a fall in pre-tax profits for the three months to the end of December to $2.05bn (£1.32bn) compared with $2.28bn in 2010.
Profit for the financial year was up to $12.37bn, from $10.97bn the year before.
The UK's second-largest drugs firm has 61,000 staff globally, of which 8,000 are in the UK.
The GMB union said shedding R&D jobs would damage the UK economy.
"These cutting edge R&D [research and development] jobs are both well paid and essential for a thriving UK economy," said Allan Black from the GMB.
'Cutting edge' jobs
The latest cuts are part of the third restructuring programme the company has carried out since 2007, and is designed to save $1.6bn a year by 2014.
Read more here