MOSCOW, January 16 - RAPSI. Renowned British lawyer Jonathan Sumption, who acted as the QC for Russian billionaire Roman Abramovich in his litigation with disgraced oligarch Boris Berezovsky in the High Court of Justice in London, has been sworn in as a Supreme Court justice in the UK, the court said in a press release.

Sumption was appointed in May, but he delayed his assumption of office until the completion of the proceedings in Berezovsky's $5.5 billion lawsuit against Abramovich.

Berezovsky seeks compensation for assets he was allegedly forced to sell Abramovich between 2000 and 2003 for significantly less than their value.

The High Court of Justice is expected to complete the case soon. Sumption made his final remarks last December. Laurence Rabinowitz, the QC for Berezovsky, will deliver his final remarks on January 17. The judge will then withdraw to consider the judgment.

Sumption has officially entered the judge office and started hearing his first case as he has already finished performing in the case.