Total exposure to crisis stands at over £27bn

Swiss financial colossus UBS has more than doubled its sub-prime writedowns to around £18.5bn, in addition to £9bn it wrote off last year.

The bank, the worst hit in Europe by the credit crisis, said it expected to post a first-quarter net loss of over £6bn.

Last year, it reported its first annual loss since it was created a decade ago.

The company also announced that its chairman and former chief executive Marcel Ospel would not be seeking re-appointment.

UBS added that it planned to raise £7.5bn in capital from the issue of new shares, and was in the process of creating a new business to deal with US property assets that had become worthless.

In a statement UBS said that it was confident that this would "deal effectively with the firm's real estate exposures and allow the bank to focus on strengthening its core operations."