More than 150,000 Northern Rock customers will receive hundreds of pounds each in refunds over incorrect paperwork in loan deals.
The mistake was not spotted for five years.
ITV News' Business Editor Laura Kuennsberg reports.
George Osborne’s smoke and mirrors in last week’s Autumn Statement continue to be exposed.
Now the Treasury has admitted that public sector net borrowing will be £270 million higher this year as a result of mistakes at Northern Rock.
But this figure was not revealed to parliament last week or in the official forecasts, even though the Treasury has admitted it knew about this problem in October.
It’s time George Osborne started being honest with people.
No amount of trickiness with the figures can disguise the fact that his failure to deliver jobs and growth means he is borrowing billions more than he planned.
Richard Banks, the boss of UK Asset Resolution Limited who are overseeing the winding down of Northern Rock, told ITV News's Laura Kuenssberg that customers were given "incomplete" and not "misleading" information about their loans.
The banking chain Northern Rock finally died today. Virgin Money, which bought the bank last November in a deal worth £747 million, has decided to terminate the brand.
A spokesman for Virgin Money said: “We have been working hard to integrate the Virgin Money and Northern Rock businesses this year.
"All of the branches have been transformed into Virgin Money Stores [and] the company has been renamed as Virgin Money plc."
The taxpayer may lose around £2bn after the assets of collapsed bank Northern Rock are wound down, The National Audit Office has said.
The public spending watchdog also said taxpayers lost approximately £480m when Northern Rock PLC was sold in 2011.
The early sale of Northern Rock to Virgin Money was the "best way" to protect the taxpayer from greater losses, the report from the spending watchdog said. Northern Rock was saved in 2008 at the beginning of the financial crisis.