Health and beauty chain Alliance Boots has announced the shock resignation of boss Andy Hornby after less than two years in the role.
Mr Hornby, who gained notoriety as the head of Halifax Bank of Scotland before its near-collapse and rescue by Lloyds TSB, has stepped down with immediate effect, according to the firm.
He said his decision follows "an intense last five years" and said he would take a few months break.
Boots executive chairman Stefano Pessina will take on his role while the firm searches for a replacement.
Today's news marks an apparent blow to Mr Hornby's career, which appeared to be back on track after his appointment as chief executive of Boots so soon after his disastrous stint at HBOS.
He was one of a number of disgraced bankers - including former Royal Bank of Scotland boss Sir Fred Goodwin - who received a very public mauling in the wake of the financial crisis which led to a series of taxpayer bail-outs.
Lloyds has been left 41% owned by the state after assuming billions of pounds of bad debts through its takeover of troubled lender HBOS.
But Mr Hornby's reign at Boots appeared trouble-free, with the group's last set of results showing a 12.7% hike in trading profits and recent sales figures revealing that the high street chain shrugged off a tough December which left many rivals under pressure.
The group stressed today that it expects to deliver "another year of strong trading profit growth" when it reports results to March 31 in May.
Mr Hornby said: "After an intense last five years as chief executive of two major companies, I have decided to take a few months break."
He added: "I have thoroughly enjoyed the last couple of years at Alliance Boots during which time the company has performed very well."
Mr Hornby also leaves behind a well-paid position, with an £850,000-a-year salary, not including bonuses.
He landed a £400,000 "golden hello" when he took on the top job at Boots in July 2009 and the firm's last annual report showed he earned a total of more than £2 million in pay and benefits for the first nine months alone.
The group will now begin the hunt for his successor, but it is thought there are two strong internal candidates - Alex Gourlay, chief executive of the health and beauty division, and Ornella Barra, head of the pharmaceutical wholesale division and long-term partner of Mr Pessina.
Mr Pessina teamed up with private equity firm Kohlberg Kravis Roberts to take Boots private for £11.1 billion in 2007.