LONDON (Reuters) - UK oil and gas major BP (>> BP plc) has appointed a new head of its Russian business with immediate effect, the company said on Monday.

David Campbell, who is currently head of the group chief executive's office in London, will become president of BP Russia at a time of political turmoil after Russia's takeover of Crimea from Ukraine.

BP is the biggest foreign investor in Russia's oil sector through its stake of under 20 percent in the Kremlin's state oil champion Rosneft (>> Rosneft' NK OAO).

BP's Russian business produces over a quarter of its worldwide oil output and holds more than a third of its oil and gas reserves.

Between 2003 and 2007, Campbell was based in Russia as a senior employee of TNK-BP, the company's Russian joint venture which was last year sold to Rosneft for $55 billion (33.05 billion pounds).

(Reporting by Karolin Schaps; editing by Sarah Young)

Stocks treated in this article : Rosneft' NK OAO, BP plc