However, analysts think that the level of mistrust between the two groups of shareholders is so great it cannot yet be assumed that the demerger is a done deal.

According to London-based Millhouse Capital, which represents Sibneft's former owner and powerful Russian magnate Roman Abramovich, "signatories intend to implement the protocol within the shortest period of time possible".

Yukos and Sibneft agreed to merge last April, and by December Yukos had acquired 92% of Sibneft in exchange for 26% of its stock and a $3 billion cash payout to Abramovich to form YukosSibneft.

However,