A parking sign error could end up costing a Welsh council more than £22,000 in refunds to motorists.
Up to 320 tickets have been slapped on the windscreens of drivers who parked in a loading bay near the city's museum during a nine-month period.
However, it has since emerged that a road sign on Burrows Place was three inches (7cm) short of the legal requirement.
Local councillor Sybil Crouch raised the issue following a deluge of complaints from those hit with the fine – which can be up to £70.
Mrs Crouch, who was among those who got a penalty notice, said: "Motorists were left confused and misled into believing the space was available for parking.
"Signs and markings like these should be clear so that motorists are not misled in to parking in a restricted area."
The Labour councillor said she then submitted a Freedom of Information request to see how many others had been booked - and was surprised by the results.
She added: "Three hundred and twenty is a ridiculous number of tickets to be issued in just nine months given that it is a very small area.
"After having robustly challenged the adequacy of the sign, the council finally conceded that it is not correct and they have ceased enforcing in this location until it is changed.
"I have also asked that all 320 recipients of a notice for this area be refunded as the sign has never been valid."
Swansea Council said it apologised for the error.
A spokesman said: "When we discovered the sign in place at the loading bay wasn't tall enough, we stopped enforcing there.
"We'll start enforcing at this location once again as soon as a new sign is installed.
"But all penalty charge notices issued at this location will be cancelled. We'll be writing to motorists to arrange reimbursement, but we'd also ask anyone who has received a penalty charge notice there to get in touch with our parking services team."