Alleged rogue trader Kweku Adoboli broke down in tears in the witness box as he began his defence against claims that he engaged in unauthorised trading that caused losses of $2.3 billion €1.8 billion) at Swiss bank UBS.

Southwark Crown Court was told yesterday that two additional charges of false accounting have been brought against Mr Adoboli, who took the stand for the first time in the six-week trial.

Mr Adoboli began his testimony by telling the jury that he did not believe the behaviour he is being accused of by prosecutors was “fraudulent”.

He said: “I do not believe the behaviour was fraudulent. What I was asked to do was help to develop processes using the tools at UBS.”

Claims that he found it easier to engage in allegedly fraudulent behaviour because of his experience in the back office were “unfair”, he said. “Half of the people on the trading floor also came from operations,” he told the jury. – Copyright The Financial Times Limited 2012