Shareholders of AstraZeneca meeting in London at the same time were due to also approve the move. Syngenta will focus on agrochemicals, or herbicides and fungicides, as well as some genetics activities. With headquarters in Basel in northwestern Switzerland, its projected turnover is seven billion dollars (eight billion euros) and it is expected to operate with 23,800 staff.

Novartis will control 61 per cent of Syngenta. The new company will be quoted on four stock exchanges - London, Zurich, Stockholm and New York - from November 13.