BP is on Thursday expected to sign an agreement aimed at preserving its 50 per cent stake in TNK-BP - Russia’s third-largest oil company - after a power struggle with its local partners that focused attention on the rights of foreign investors in Russia.

The memorandum of understanding, agreed this week by BP’s board, follows a long-running dispute over BP’s most important international venture. It supplies 25 per cent of the company’s oil and gas production.