A former UBS trader accused of unauthorized dealing that cost the Swiss bank $2.3 billion was expected to enter a plea for the first time on Tuesday in a case that led to the resignation of UBS's chief executive.

Kweku Adoboli, 31, who worked as a director of exchange traded funds, has been charged with two counts of fraud and two of false accounting and will appear at Southwark Crown Court at 1400 GMT.

UBS said it had uncovered rogue trades that took place between October 2008 and December 2010.

Oswald Gruebel resigned as chief executive in September, saying the losses had shocked him deeply and UBS needed a new leader.

Adoboli, the British-educated son of a retired United Nations official from Ghana, was arrested in London on September 15 and charged a day later.

At a previous hearing, his lawyer said Adoboli was appalled at the scale of the consequences of his disastrous miscalculations.

Adoboli last week switched legal teams ahead of his court appearance. London law firm Bark & Co, which specializes in fraud cases, said on Friday it was now representing Adoboli.

Kingsley Napley, which had until then been representing Adoboli, confirmed it was no longer working on the case. A spokeswoman would not say why Adoboli had parted company with the law firm.

(Reporting by Peter Griffiths, Editing by Mark Potter)