The district is a safer place now a violent gang of teenage drug dealers is behind bars, says St Albans' top cop.

Ch Insp Mike Todd was reacting to the success of Operation Luge, a massive police initiative in response to a spate of knifepoint offences in St Albans and London Colney over a 10 month period.

Eighteen-year-olds Isaac Wallace-Greaves and Kai Henry-Smith, Kobi Nelson, 19, and Harley Kavanagh, 17, wielded swords and machetes in their attacks on rival dealers. They have been jailed for a total of 42 years for conspiracy to commit robbery and conspiracy to commit GBH.

Ch Insp Todd said: “It was a very complex conspiracy investigation, with increased challenge due to a lack of support from witnesses and victims.

"Without the tenacity of the officers involved, especially Det Sgt Tom Evans and Det Con Jody Perrin, as well as a team of officers, these dangerous young men could have escaped justice.

“The St Albans district is a safer place now that they are all behind bars.

“I hope this is a stark warning to anyone who thinks they can use violence and threats that we can, and we will, do everything in our power – with or without victim and witness support – to tackle violent crime and gang culture.”

One attack, in York Road, St Albans, resulted in a man being slashed in his hands and arms.

A witness said: “Shouting was coming from the street. I couldn’t work out what was being said but it sounded frantic.

“The incident was chaotic with the group running around and yelling - it was like they didn’t have any idea what they were meant to be doing, like they didn’t have a plan.”

“A male who was sitting in the passenger seat was holding a knife but it was the size of a machete."

And a witness to an attack at Sainsbury’s in Colney Fields said: “I could see a man on the ground and he had lots of injuries to his face and had blood over him. He seemed to be unconscious.”