John Thain is giving us a tour of what is soon to become America's most infamous office, with its $87,000 rug, $68,000 sideboard, $28,000 curtains – all part of a $1.2m redecoration scheme. This was early December, a little under two months before Thain would be fired in the same room by his new boss, Ken Lewis, chief executive of Bank of America.

For now, before a price tag had been placed on every item in his office, the 53-year-old chief executive of Merrill Lynch was in high spirits. The worst year on Wall Street in nearly a century was coming to an end, and Thain could rightfully claim to have saved his bank from ruin. Over a weekend in mid-September, as Lehman Brothers collapsed into bankruptcy, Thain pulled off a coup: he persuaded BofA, one of the few financial giants in the US that didn't need government money to survive, to pay $29 per share for his own firm, even though Merrill was days away from following Lehman into bankruptcy.

Thain had taken over as Merrill chief executive nine months before that weekend deal. Now, he appeared to be one of the few Wall Street leaders who grasped the enormity of the credit crisis. Thanks to his analytical approach to the marketplace, it seemed, Merrill shareholders could look forward to a stake in Bank of America. “I have received thousands of e-mails saying, ‘Thank you for saving our company',” Thain told us that day. And yet he admitted that the decision to sell Merrill Lynch – a 94-year-old institution that was always “bullish on America” – had been painful. “This was a great job. This was a great franchise. Emotionally, it was a huge responsibility.”