The judge in the trial of alleged UBS rogue trader Kweku Adoboli told the jury on Monday not to let their views about the banking industry influence their judgment.
Adoboli, 32, has been blamed for a loss of $2.3 billion at the Swiss bank in September 2011. He denies two counts of fraud by abuse of position and four of false accounting.
"You don't need me to tell you that this case has been no ordinary trial," judge Brian Keith told the jury as he began his summing-up, the final leg of the long-running trial before they retire to consider their verdict.
"How could it have been when the man you're trying was an apparently respectable trader at a famous investment bank whose trading on behalf of the bank led to a loss so colossal that it exceeded $2 billion?"
The prosecution say Adoboli traded far in excess of his risk limits, concealed his positions with fictitious bookings and lied to the back office. They say he was driven by a gambling addiction and a desire to be a star trader.
Adoboli says he did not act dishonestly because everything he did was aimed at making profits for the bank, because others knew of his methods and in some cases used similar ones, and because managers encouraged rule-bending in pursuit of profits.
"Don't let what some of you may think about banks and the people who work for them influence you unduly," Keith told the jury.
"There's been a lot of talk in recent years about the bonus culture, failing banks having to be bailed out," he said, adding that there were always two sides to every argument.
He told the jury they were not there to find someone responsible at all costs for the loss that UBS had suffered. They should not convict Adoboli just because they felt it would be wrong for no one to be held criminally responsible for the loss.
"You should not approach the case on the basis that banks have only themselves to blame. You should not allow yourselves to be deflected (by) views you have as to whether banks are a force for good or a force for evil in our society," he said.
The judge will continue his summing-up on Tuesday.