US pharmaceutical giant Pfizer could make a hostile bid for AstraZeneca as early as today.
Its £63 billion takeover offer was rejected after the UK company said it "substantially" undervalued the business.
That has forced Pfizer to consider its next move, with industry experts believing a hostile bid - which would aim to bypass the AstraZeneca management and target shareholders directly - could come soon.
Last week, Pfizer insisted it was committed to building a research and development hub in Cambridge which was planned by AstraZeneca.
The £300m base at the Cambridge Biomedial Campus would house about 2,000 researchers.
But a hostile bid would trigger increased calls for the offer to be referred to the competition authorities and would also heighten union fears over jobs if the takeover was successful.