Mr Peter Sutherland has resigned from the board of Allied Irish Banks, saying his workload as chairman of British Petroleum was too great and would prevent him devoting enough time to the bank.

"I have served six years with AIB, which is the normal term for a director. I knew, and I said at the time, that once I was appointed as chairman of BP I would probably have to give up certain positions," Mr Sutherland told The Irish Times last night.

Mr Sutherland, who is also the chairman and managing director of Goldman Sachs, served as AIB chairman for more than three years, remaining on as a non-executive director.

AIB said it had accepted his resignation "with regret", but added that it had been intimated when Mr Sutherland was appointed chairman of BP "that he would be reviewing his heavy business commitments".

"We are very sorry to lose Peter, who has made a tremendous contribution to AIB," said Mr Lochlann Quinn, the current chairman of the bank.