Businesses selling alcohol are being warned by Luton Borough Council to take extra care about under age sales.
A crack down last week by Trading Standards and Police officers resulted in three of the six shops visited, selling alcohol to a 16-year-old police cadet volunteer.
Councillor Aslam Khan said: “We are very disappointed to find these traders, two of whom had been caught selling alcohol to children before, are still breaking the law.
“In the third case, it was clear the seller simply had no idea what they were doing.
“The Council and the Police will not tolerate the health of children being placed at risk by traders who sell alcohol to them, or don’t ensure their sales staff are properly trained.”
The council is increasing undercover inspections to ensure local businesses are operating within the law.
Businesses face potential prosecution and a review of their license to sell alcohol.
If you believe a shop is selling alcohol to children, call 03454 040506.