A scandal is unfolding at the British bank, the Co-operative Group, after its its former banking chairman, Paul Flowers, was caught on camera allegedly buying drugs.
It is a bank that has promoted its ethical investments.
But an investigation has been launched after a newspaper released footage of Mr Flowers allegedly buying hundreds of dollars worth of drugs including cocaine and crystal methamphetamine.
On Wednesday, the current chairman of the bank, Len Wardle, resigned over the matter.
He was on the board that originally appointed Paul Flowers, a Methodist church minister.
The BBC reported that the scandal followed a financial crisis at the bank.
Mr Flowers, 63, apologised after he was filmed, and Mr Wardle, said he felt it was "right" that he, himself, stepped down now.
Questions raised
It has also emerged that Mr Flowers stepped down as a city councillor in Bradford in 2011 after adult content was found on a computer he had used.
The council said the content was "inappropriate but not illegal".
Questions have now been raised about Mr Flowers's appointment as chairman of the Co-op Bank in 2010, and banking regulators will be questioned by MPs on the issue.
The Co-op Group said Mr Wardle had resigned "with immediate effect". He had held the position since 2007 but announced last month that he would retire in May 2014.
In a statement, he said the "revelations" about Mr Flowers had raised "serious questions for both the bank and the group".
"I led the board that appointed Paul Flowers to lead the bank board and under those circumstances I feel that it is right that I step down now," he added.
Mr Flowers, who was chairman of the bank from April 2010 until June this year, said his actions were "stupid" and "wrong". He has been suspended from both the Labour Party and his church.
Mr Wardle will be replaced by Ursula Lidbetter, who is the Co-op Group's deputy chairwoman and chief executive of the Lincolnshire Co-operative Society.
