The BBC is to be forced to reveal secret sweeteners contained in its licence fee collection deal with Capita within five weeks.
The Information Commissioner's Office (ICO) today gave the corporation a 35-day deadline to disclose the incentives written into the contract.
BBC bosses had previously refused requests for the detail under the Freedom of Information Act, claiming disclosure was not in the public interest because it could damage their negotiating position in future.
Public bodies frequently cite this exemption when refusing to release contract details. But the ICO said the public interest outweighed such concerns in this case.
"As the UK's largest independent public broadcaster, the BBC must ensure that they are as open as possible to the UK licence payers they serve," said head of policy delivery Steve Wood.
"On this occasion, the BBC incorrectly applied an exemption under the belief that it was not in the public interest for the corporation to release details of the incentives they offer to one of their contractors.
"However it is our view that the corporation must be open to public scrutiny in order to show the many people who regularly watch their programmes, listen to their radio stations and use their website that they continue to provide value for money."
A BBC spokeswoman told The Register: "We note the ICO's decision and are considering our response."
Capita has held the TV licensing contract since 2002, when it took over from the Post Office.
Last year it collected £3.4bn and on its website it boasts it has reduced the rate of TV licence evasion from 5.7 per cent to 5.1 per cent.
The Freedom of Information Act is proving an irritant to the BBC. Under pressure from campaigners, last year it began publishing the pay and expenses of top executives and stars. The data revealed lavish spending on taxis and other apparent profligacy, which has provided ammunition for the corporation's enemies.
Some details of the licensing operation remain secret though. In 2008, the ICO sided with the BBC when it said the workings of its famous "detector vans" should remain shrouded in mystery. ®