A 14-year-old girl was able to buy booze in half of the Nelson stores she went into, police have revealed.

Officers carrying out a test purchasing operation in 15 shops were shocked to find some cashiers did not even look up to see who they were serving.

Police and trading standards officers visited corner shops and mini-supermarkets on Saturday and handed out £80 penalty charge notices to anyone who served the youngster.

Seven stores broke the law. Sgt John Fryer said £1,040 worth of tickets had been given out, with some stores receiving two, one for the cashier and one for the licensee.

Sgt Fryer said: "We did some of the smaller supermarkets as well as the corner shops.

"A lot of the problem is they're employing a lot of staff on different shifts. They've all received the correct training, they've got written records of it, but the staff aren't switched on - they're putting things through on auto-pilot.

"When we do test purchases we put an officer in the store who watches the sale take place. In certain stores they never look up. They put the goods through, say £3 or whatever and next customer. They didn't even look at who they were serving."

Officers will be revisiting stores which failed the test purchase operation and warning traders they could lose their licence if they continue to serve youngsters.

Sgt Fryer said if stores used Lancashire Trading Standards' Check 21 initiative they would never be caught selling to under-age customers.

He added: "Check 21 is something police and trading standards advocate. If a customer does not look 21, ask for ID. If they implement the Check 21 policy they will never fail test purchases."

Kate Ison, a spokesman for the British retail Consortium, said tackling underage sales was a top priority and young people should expect to be challenged about their age.

She said: "The retail industry has generally admitted that it's not perfect and we need to all club together. We've been working with the Home Office and have started the retail alcohol standards group. That incorporates large supermarkets as well as off-licences across the industry.

"We've launched new signage. We're trying to bring about a culture of young people being expected to be challenged on their age. Training and signage are our two priorities. They are at the top of our agenda at the moment to get this sorted out.

"We need to have a co-ordinated an consistent approach at ground level to sort this out."