A defence lawyer for accused UBS "rogue trader" Kweku Adoboli told a London court on Thursday that far from acting alone, the ex-trader had learnt his behaviour from UBS colleagues.

Adoboli, 32, was arrested on Sept. 15, 2011. He is now on trial for fraud and false accounting that cost the Swiss bank $2.3 billion. He has pleaded not guilty.

His lawyer Charles Sherrard told Southwark Crown Court that Adoboli's three colleagues on the Exchange Traded Funds desk had actively taken part in some of the fraudulent behaviour he is accused of.

He said they had later "stabbed him in the back and left him to bleed on the prison floor" after he ran into trouble.

Sherrard said Adoboli had learnt some of his ways, such as the use of an illicit "umbrella" account to disguise his true trading position, from others in UBS and that there had been, and perhaps still were, other "secret books" within the Swiss bank's trading accounts.