A banker living in the East End was arrested in a police raid yesterday on suspicion of rogue trading which could have cost finance giant UBS �1.2 billion.

City of London Police swooped on a central London office in the early hours of yesterday morning and arrested Kweku Adoboli, 31.

They confirmed that they were called at 1am by the Swiss banking giant over an allegation of fraud against one of their employees.

UBS confirmed today that is has discovered a loss to the tune of $2 billion – more than �1.2 billion – due to “unauthorised trading”.

Mr Adoboli, who recently moved to a modern development in Whitechapel and had a luxury flat in Spitalfields before that, is still being held by police after being arrested on suspicion of fraud by abuse of position.

The loss is thought to be one of the biggest ever accrued by a single trader based in London.

No jobs at UBS would be affected as a result of the loss, the firm insisted amid the bleak news that its shares slid by more than ten per cent yesterday.

City of London Police said in a statement: “At 1am on 15 September the City of London Police was contacted by UBS about an allegation of fraud against one of their employees, and at 3.30am detectives from the force arrested a 31-year-old man at a central London business premises on suspicion of fraud by abuse of position.

“The man was taken to a City of London police station for questioning and he remains in custody while officers are continuing to investigate this matter.

A UBS spokesman said: “UBS has discovered a loss due to unauthorised trading by a trader in its investment bank. The matter is still being investigated, but UBS’s current estimate of the loss on the trades is in the range of USD 2 billion. It is possible that this could lead UBS to report a loss for the third quarter of 2011.”