Roman Abramovich has falsified passport to fool court, says Boris Berezovsky's girlfriend

Boris Berezovsky's partner accuses Chelsea FC owner of trying to cover up key meeting in £3.5bn case

The expression of Chelsea owner Roman Abramovich has drifted between emotionless and plain boredom as he has sat for more than two weeks at London's Commercial Court listening to evidence in an attempt to part him from the small matter of more than £3.5 billion.

Yesterday brought some respite for the Russian, as his shiny-pated nemesis Boris Berezovsky made way in the witness box for long-term girlfriend Yelena Gorbunova, 21 years his junior.

But any improvement in mood did not last long as Ms Gorbunova, 44, promptly accused Mr Abramovich of falsifying stamps in his passport. "We know everything we need to know about the stamps in Mr Abramovich's passport," she told Mr Abramovich's barrister Jonathan Sumption QC. "Strange metamorphoses are happening to these stamps," she added, with the help of a Russian interpreter.

Who was where and when in the month of December 2000 is crucial to the case. Mr Berezovsky is suing Mr Abramovich for more than $6bn over claims he forced him into selling shares in a number of lucrative companies at heavily discounted prices, or face their re-appropriation by the Kremlin and the continued imprisonment of one of Mr Berezovsky's friends, Nikolai Glushkov, who also gave evidence yesterday.

Mr Abramovich claims a crucial meeting between the pair at Mr Berezovsky's chateau on the French Riviera in December 2000 never took place as both he and Mr Berezovsky were out of the country. Mr Berezovsky has since changed his mind on the precise date based on both his and Mr Abramovich's passport stamps.

Intriguingly, Ms Gorbunova has also claimed in written submissions to the judge, Mrs Justice Gloster, that she accompanied Mr Berezovsky on a trip to the US just before Christmas, yet her passport suggests otherwise. Asked why the stamps were not there, she answered: "I don't know. But I was there."

Mr Berezovsky admitted on Monday that a number of his witnesses stand to gain financially if he wins the action. The same question was put to Ms Gorbunova, who answered: "Naturally. We are a family."

The court has heard about the complexities of Mr Berezovsky's finances but there was surprise that he may have borrowed money from Ms Gorbunova to fight the case. "Was it agreed he would pay it back if he was successful in this action?" Mr Sumption asked. "I think it's natural to assume so," she replied.

Mr Berezovsky's finances are certainly less fluid than when he arrived in the UK as a political exile in 2000, though the couple still live in Bakeham House, a £20.5 million estate in Surrey.

In July Mr Berezovsky agreed a divorce settlement with his estranged wife Galina for in excess of £100m. He has said in this trial that they have an agreement if he wins the case.

Nikolai Glushkov, godfather of one of Ms Gorbunova and Mr Berezovsky's children, was arrested and imprisoned in Moscow in December 2000 over allegations of financial impropriety when he was deputy director of Russian airline Aeroflot. It was his imprisonment that Mr Berezovsky claims was crucial to Mr Abramovich's blackmailing of him.

Mr Glushkov told how he had been warned by friends before his arrest that he would be killed on his way to the Public Prosecutors Office. "I was told the way it would happen," he said. "I would be run over by a truck."

The case continues.