Knife-related crime remains lower in Hertfordshire than in other parts of the country, but the campaign aims to reinforce the message that carrying a knife is illegal and will not help to keep you safe.

Test purchases took place at stores in Hitchin, Letchworth and Royston.

Student volunteers from the North Herts College Uniformed and Protective Services course assisted officers with the operation, which involved two under-18 students attempting to buy a knife or alcohol without identification.

A total of 12 stores were visited last week. In four attempts to purchase a knife, the students were sold one once, while on 10 attempts to purchase alcohol the students were sold it on two occasions. Following each attempt, officers debriefed the stores about the test purchase and the outcome.

Community Safety Unit Sergeant Chris Adshead said: "The majority of stores refused the sale of underage products and correctly asked for identification, however there is work to do for those who failed the test".

"We will be working closely with Trading Standards to ensure that those outlets which sold age restricted products are aware of their legal obligations".

"We will continue to conduct such operations to ensure the safety of under 18s".

"I'd also like to thank students from North Herts College who volunteered for the initiative and hope it gave them a real insight into aspects of policing."