The taxpayer might not recoup the £45 billion spent bailing out the Royal Bank of Scotland for another decade, according to the bank's outgoing boss.
Stephen Hester, whose departure later this year from the 81% state-owned bank was announced earlier this month, said privatising RBS was a long-term project.
Of the £45 billion figure, Mr Hester told the Sunday Telegraph: "There has never been a privatisation that raises that much in one go. So it is most likely that it would be, if you do it conventionally, four or five goes over 10 years.
Mr Hester said he did not feel any anger about his impending departure, which when it was announced he called "a board decision, not mine."
He added: "Part of me did want to see the job fully through, did want the champagne and roses of a successful privatisation.
"Another part of me thought goodness me, this job drives me nuts from time to time and how long do I want to do it for?
"I genuinely mean that I am comfortable with what has happened. I think RBS is in much better shape than we had any right to think it could be."
Meanwhile, it has been reported that Mr Hester could walk away from RBS having received as much as £14 million from the bank he joined in 2008 when it was on the brink of collapse.
The Sunday Times said that adding his salary, bonuses and up to £4 million in share payments he could still receive, the banker's pay package would average about £2.8 million a year.
However, he could have earned up to £40 million under the package agreed when he was hired in 2008, while he is paid less than any other boss of a large British bank.