U.S. pharmaceutical group Pfizer Inc has told Prime Minister David Cameron it will retain British jobs and a planned scientific research hub in Cambridge if it succeeds in its bid to take over rival AstraZeneca

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Pfizer laid out a number of pledges in a letter to Cameron, including establishing the combined company's corporate and tax residence in England and completing a substantial R&D innovation hub in Cambridge, eastern England.

Pfizer also vowed that 20 percent of the combined company's total R&D workforce would be in Britain if the deal goes ahead.

"We would like to assure the government of our long term commitment to the UK where Pfizer already employs a significant number of colleagues across Research, Commercial, and Administrative roles," the company said on Friday.

(Reporting by Paul Sandle; editing by Kate Holton)