A banker who is suing Lehman Brothers for $16.5m (€15.3m) of unpaid bonuses has told a London court that the bank made "some questionable accounting decisions' during the 1998 Russian crisis.

Kuwaiti-born Derhalli, of Kensington, west London, who is now global head of commodities at Deutsche Bank, is suing Lehman for constructive dismissal and breach of contract. He was originally hired by Lehman in 1996 to set up its Eastern Europe emerging markets office in London. He was given special responsibility for Russia and recovering the bank's investments after the 1998 crisis.