UPDATE 1-Abramovich seeks London court approval to sell Norilsk Nickel stake

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LONDON, Feb 27 (Reuters) - Chelsea soccer club owner Roman Abramovich's Cyprus-based Crispian on Tuesday sought a London court's permission to sell 2 percent of Norilsk Nickel to billionaire Vladimir Potanin, a move aluminum producer Rusal is trying to block.

Potanin offered to buy a 4 percent stake in Nornickel from Abramovich for $1.5 billion. However, Rusal, which also owns a stake in the mining group, is seeking a court injunction to block the deal.

Potanin's Cyprus-based Whiteleave exercised its right to buy 2 percent of Nornickel last week, requiring the shares to be handed over on Feb. 28, Crispian's lawyer, Daniel Jowell, said.

An earlier agreement involving Potanin and Rusal, which is controlled by businessman Oleg Deripaska and holds 27.8 percent of Nornickel, allowed them to share Abramovich's stake on a pro rata basis if they both wanted to buy it.

The latest ownership dispute revives a long-running battle for control of Nornickel between Potanin, who owns a 30.4 percent stake in the miner, and Deripaska.

Abramovich and his partners hold a 6.3 percent stake in Nornickel, of which 4.2 percent is owned via Crispian.

Crispian, which previously agreed not to transfer its shares in Nornickel until the hearing is over, asked the London court on Tuesday to release it from the undertaking to freeze the deal until the next hearing, which is expected on March 8-9.

Crispian is worried that if it cannot transfer the shares, Whiteleave will walk away. Crispian estimates potential losses from a failure of the whole deal at $271-821 million.

A lawyer for Whiteleave also asked the London court to allow the 2 percent share sale to proceed, but with a commitment not to sell on these shares or accept any dividends on them before a court decision and to return them to Crispian if the court finds in Rusal's favor. (Reporting by Peter Hobson writing by Polina Devitt editing by Louise Heavens and Alexander Smith)