A Swindon bar is to stop selling alcohol for six days after staff were caught serving underage drinkers.
Mackenzies, in Wood Street, will also have to close for 48 hours as part of the penalty imposed by the borough council.
Trading Standards sent youngsters into bars to test if they would get served.
The bar's owner, Gael Mackenzie, said measures were in place to stop underage drinkers being served, but an error had been made and the penalty was fair.
Mr Mackenzie said: "The venue doesn't have a problem with underage drinking, it's more to do with controls that weren't being implemented and - hands up - we were caught out and we are paying the price for that."
He said the member of staff who served the underage customer had been given an £80 penalty ticket.
"It really shouldn't have happened and we are reviewing our procedures," he said.
"When we close we'll be having some of the police training people come up to reinforce the message to the staff."
Lionel Starling, head of licensing at the council, said the bar had 21 days to appeal against the penalty.
He said that during the alcohol-free period the bar would be allowed to open as a cafe serving soft drinks and food.