The council could have to pay out thousands of pounds to drivers after a technical error in the introduction of new car park charges.
A public notice published in February introducing new fees at six Brighton and Hove City Council car parks has been revealed not to be legally binding because it was issued before a public objection over one of the changes had been resolved.
It means that the council will now have to refund anyone who has paid one of the new rates since they were introduced on Thursday 1 April.
Drivers will be able to claim money back if they can show proof that they paid for parking tickets for any of the following specific time periods at the individual car parks: Black Rock car park, four to nine hours (£5); Norton Road car park, two to four hours (£2) or nine to 12 hours (£4.50); Oxford Court, up to two hours (£2); The Lanes, up to one hour (£2.40); London Road, two to four hours (£3); Regency Square, up to one hour (£2), one to three hours (£4.50), three to four hours (£6.50) or the evening rate between 6pm and midnight (£4.50).
The council plans to publish a new public notice to correct the mistake.