SHOPKEEPERS are being warned to make sure staff do not sell knives to youths under 18 after stores were caught out in an undercover sting.

A blitz by police and Trading Standards officers revealed a number of shops still selling blades to under-18s despite a crackdown in the law.

Shops in Colchester and Clacton were targeted in the operation. A total of seven stores in Colchester borough and another seven in Tendring district were targetted.

Three shops in each area failed the inspection.

Sgt Matt Mallett said: “While the majority of the shops we tested were selling within the law, there were a few incidences where young people were able to purchase blades illegally.

“We would urge all store managers to make sure their workers are equipped with the right knowledge when it comes to knives.”

The warning follows recent knife incidents in Clacton.

Last month a 15-year-old boy was robbed at knifepoint by two youths at the Knox Road playing fields.

His attackers escaped with his £100 mobile phone.

The victim was left shocked by the ordeal, but luckily was unhurt.

A teenager was also discovered suffering from a stab wound on bank holiday Monday, in an alleyway between Timley Close and Langham Drive, Clacton.

A woman was arrested, but later released without charge. Police said they were taking no further action.

Sgt Mallett said it was an offence to sell any knife, blade, razor blade, axe or any sharp instrument to anyone under 18.

Shop staff caught making illegal sales could face a fine or even prison.

Sgt Mallet added: “Don’t take chances with guessing a customer’s age.

“Ask for identification and refuse the sale if they can’t produce a valid ID.

“It is the law and there are no excuses.”