Barclays' (LON:BARC) deputy chairman Mike Rake is leaving the British banking group to take up the chairmanship at payment firm Worldpay.
Rake, who is also the chairman of telecoms group BT (LON:BT.), is understood to have told Barclays' chairman John McFarlane of his decision last week.
The move comes hard on the heels of the departure of the bank's chief executive Antony Jenkins last week.
McFarlane has taken on the role of chief executive while Barclays searches for Jenkins' successor.
Jenkins took over the top role at Barclays after Bob Diamond and other former executives left in the wake of the financial crisis and subsequent scandals.
As its senior independent director (SID), Rake played a key role in Jenkins' departure.
When Jenkins quit, Rake said in a statement: "It became clear to all of us that a new set of skills were required."
Barclays said Rake intended to continue as the bank's deputy chairman and SID "at least until the end of 2015".
Worldpay, owned by Advent International and Bain Capital, is said to be preparing a possible £6bn listing on the London stock market later this year.
Barclays shares rose 0.9p to 276.9p in mid-afternoon trading in London.