Rodney Galpin, brought in from the Bank of England in 1988 to perform both tasks at a time when the bank was struggling to revive its businesses, also announced that he would retire at the annual meeting next spring. He is 61.
Before Mr Galpin goes he will be replaced as chief executive by Malcolm Williamson, the managing director, who steps into the new job in January. The new chairman is to be the oilman Patrick Gillam, now a deputy chairman and formerly a managing director of BP.
Standard said Mr Galpin had publicly declared more than a year ago that the roles would be split, and the announcement was not a direct response to the Cadbury report. However, a spokesman said corporate governance issues had played a part in the bank's decision.
The move leaves Barclays isolated among the big banks, since the chief executive, Andrew Buxton, is to take over the chairmanship as well from January, when Sir John Quinton retires.
Mr Buxton is under institutional pressure to transfer the chief executive's job to someone else and has already given ground by indicating he will consider whether the workload requires a split, although not until after he has spent some time in the job.
Barclays' problem is that it has two powerful chief executives already running the main businesses. They are Alastair Robinson and David Band and neither would welcome a chief executive appointed above his head.
Wembley said it would separate the roles of chairman and chief executive, with Sir Brian Wolfson becoming executive chairman and Alan Coppin managing director.Reuse content