Police officers have asked pupils at a Stevenage secondary school to walk through a knife arch, designed to detect concealed metal objects, in a bid to tackle a rise in crimes involving knives.

In the first event of its kind, Herts police ran an anti-knife crime initiative at The Nobel School, which involved all Year 10 pupils entering the school via a knife arch before listening to presentations by officers.

Knife crime in Hertfordshire has increased by 44 per cent in the last three years.

Nationally, Herts has seen the largest proportional increase in the UK during this time.

Neighbourhood Sergeant Nic Achilleos said: “This is just one of the initiatives we are rolling out across the town to try to educate young people about the dangers and consequences of carrying knives and other bladed weapons.”

Detective Constable Graham Anness said: “Like the rest of the county, Stevenage has seen an increase in crimes reported which involve knives, and addressing this issues is a policing priority for us.

“We are trying to prevent these types of crimes occurring and have a range of educational initiatives which we are rolling out to cover all age groups.”

Nobel’s headteacher, Martyn Henson, said: “We are very grateful to the officers for running this initiative.

“Carrying a knife can lead to tragedy. We are determined to keep Nobelians safe at all times.”

The Comet reported two weeks ago how violent drug gangs have taken hold in Stevenage, with a Comet source - whose identity we are protecting - confirming there are pupils in the town’s secondary schools who are county lines gang members.

County lines is drug dealing involving criminal networks from urban areas expanding into smaller towns and rural areas.

Asked if there are Nobel pupils who are county lines gang members, Neighbourhood Inspector for Stevenage, Simon Tabert, said: ”As the nature of knife crime and its links to county lines is a hidden problem, police do not have accurate and thorough intelligence on the extent to which children in the town are at risk.

“We do know the problem is not confined to a specific part of Stevenage, or school catchment area.

“We are gathering data on the extent to which young people are at risk. Meanwhile, we are working with all schools in the town to help build resilience within their population and protect their pupils.

“The event at Nobel was the first event of its kind, and more are being planned at other schools.”