Britain's Financial Services Authority (FSA) regulator has started a formal enforcement probe against Swiss bank UBS over last year's $2 billion (1 billion pounds) trading loss at UBS's London arm.

On 16 September 2011, the Financial Services Authority and the Swiss Financial Market Supervisory Authority (FINMA) announced the launch of an independent investigation into the events surrounding trading losses incurred by UBS AG (UBS) in the London operations of its Investment Bank, the FSA said in a statement on Friday.

The FSA has now commenced a formal enforcement investigation against UBS and is in close contact with FINMA which has also commenced enforcement action against UBS, it added.

(Reporting by Sudip Kar-Gupta; Editing by Hans-Juergen Peters)