AstraZeneca is to cut 8,000 jobs worldwide as it embarks on outsourcing more of its research and development.
Some of the work is due to be transferred to China in a move cut costs, it has been widely reported.
Shares in the company fell 140p to 2905p, wiping £2 billion from its market capitalisation and making it the biggest faller in the FTSE 100.
David Brennan, chief executive of the AstraZeneca said: “As the majority of our employees are in the UK, the US and Europe, you could expect more job cuts there