US drugs company Pfizer has contacted AstraZeneca over a possible multi-billion euro takeover.
Pfizer said it had approached AstraZeneca in January with a 71 billion euro bid and after limited talks AstraZeneca pulled out of negotiations.
Pfizer said market conditions have prompted a second bid.
AstraZeneca said it had considered talks with Pfizer, but will continue with its independent strategy.
The British company currently employs 6,700 people, but has laid off thousands as it deals with a drop in sales and losses of income from lucrative patents.
AstraZeneca currently acccounts for 2.3 percent of all British exports.