Villiger was reacting to a ruling by the Federal Administrative Court last week that the transfer of customer data broke the law. His comments were published by the German-language Tages-Anzeiger newspaper on Wednesday.

The court decision has cast doubt on the agreement reached between the authorities in the US and Switzerland last year under which the Swiss agreed to hand over data on an estimated 4,450 bank customers.

Villiger said in the newspaper interview that the ruling had placed the bank and the country in a “extremely difficult situation”.

There have been calls within Switzerland for UBS to take responsibility for its past actions, which encouraged US tax payers to transfer funds to Switzerland in order to avoid paying taxes, something Villiger rejected.

“There can be no solution without an agreement between states,” he said. He further pointed out that those at the bank who had been responsible for the crisis had now left.

He added that it was difficult to draw up a sustainable strategy for the bank when there was so much uncertainty about many aspects of its work, including the future of bank secrecy.