Two Russian Jewish businessmen faced each other in court yesterday on the first day of a high profile case against Chelsea FC owner Roman Abramovich.

Mr Abramovich has been accused of the betrayal and blackmail of his former business partner Boris Berezovsky. The pair, among the world's richest men, worked together following the collapse of the Soviet Union but fell out several years ago.

Mr Berezovsky has claimed that Mr Abramovich used "threats and intimidation" to coerce him into selling his stake in Russian oil company Sibneft at below value. He is seeking £3.2 billion in damages for breach of trust and breach of contract.

Mr Berezovsky's lawyer, Laurence Rabinowitz QC, said that when Mr Berezovsky fell out of grace with the Russian leadership in 2000 and left his home country, Mr Abramovich "was in effect required to make a choice" whether to remain loyal or to "profit from his difficulties".

He added: "Mr Abramovich at that point demonstrated that he was a man to whom wealth and influence mattered more than friendship and loyalty and this has led him, finally, to go so far as to even deny that he and Mr Berezovsky were actually ever friends."

In a statement before the hearing Mr Abramovich's lawyer Jonathan Sumption dismissed the allegations, and suggested they were motivated by Mr Berezovsky's desire to cement himself as "the leader of the opposition to the present government of Russia".

The trial, at the Commercial Court in London, is not expected to reach a conclusion for at least two months.