Paul Flowers, the former Co-operative Bank chair who was nicknamed the Crystal Methodist, has been banned from the financial services sector by the Financial Conduct Authority (FCA) - five years after he presided over the lender's near-collapse.
Flowers led the bank from April 2010 until June 2013, when a £1.5bn hole in its balance sheet was revealed.
Flowers, a methodist minister, endured a catastrophic grilling by MPs, in which he revealed himself as heavily inexperienced in the financial sector, with one member of the Treasury Committee describing him as "a thoroughly inadequate witness... either economical with the truth or plain incompetent".
Shortly afterwards, a video by the Mail on Sunday revealed he had spent £300 on crystal meth and cocaine, as well as trying to buy ketamine. He also sent texts boasting about using ketamine and GHB.
Today the FCA said Flowers had "demonstrated a lack of fitness and propriety required to work in financial services".
He also used his work email account to send and receive sexually explicit messages, and to discuss illegal drugs, and used his work mobile to make calls to a premium rate chat line.
“Flowers failed in his duty to lead by example and to meet the high standards of integrity and probity demanded by the role," said Mark Steward, executive director of enforcement and market oversight at the FCA.
"These high standards are what the financial services industry and the wider community rightly expect of its senior individuals. Where a chair, or other senior individual, fails to discharge these standards the FCA will hold them to account.”
Flowers' ban came as the economic secretary to the Treasury, John Glen, appointed the Prudential Regulation Authority's (PRA) Mark Zelmer to launch a long-awaited independent review into the Co-op Bank between 2008 and 2013.
The investigation will cover the period during which it withdrew from the bidding process to buy 632 bank branches from Lloyds in 2013.
The government pledged to launch the review back in 2013, but has waited until the FCA concluded its regulatory action.