The sale of Clydesdale Bank in the UK may be back on the radar of the board of National Australia Bank.Michael Chaney, chair of the board of NAB, told the annual general meeting, held in Sydney yesterday, that the bank's British business were one of the "deadweights" in the bank's business mix, according to a Herald Sun report."But we are working very hard to resolve those issues and we have some confidence that we will be an outperformer as we go forward," he said.Chaney said NAB would focus on its core businesses in Australia and New Zealand, "while endeavouring to make whatever portfolio moves seem sensible elsewhere in the world".He said "that might include the sale of the British banks ... depending on opportunities." Chaney also said the board "had a lengthy session" this week to discuss growth in Asia.The NAB chairman also used the AGM as an opportunity to dismiss as "absolutely ridiculous" suggestions that banks be made subject to a super-profits tax.