Lynn Dukes, who has been co-ordinating one of Europe's most complex office moves, costing pounds 300m and involving 4,000 people, is resigning for personal reasons and will leave in the next few weeks.
Dukes's responsibilities will be carved up and give Bob Diamond, the chief executive of global markets, a pivotal role in the move through his new control of the IT function.
Diamond, recruited from CS First Boston in the summer on a rumoured salary of more than pounds 5m, has assumed responsibility for IT, which is expected to account for more than pounds 100m of the costs of the move to Canary Wharf.
A BZW spokesman said Dukes's departure would not impair the move, which is running smoothly on time and to budget. Andy Bruce, head of credit and risk management, who has chaired the committee overseeing the move will take on responsibility for the task. Other members of the team which has been involved with the move are still in place.
Dukes's responsibilities at BZW, which included IT, operations and the finance function, will now be allocated across the management team which is being put together by Bill Harrison, BZW's new chief executive.
BZW is making the move to Canary Wharf to allow it to bring together all its staff under one roof. The first staff are expected to move to Docklands in April next year.