A covert cannabis farm hidden beneath the M1 has been shut down after police — aided by a quick-thinking local farmer — uncovered more than 240 plants growing inside a drainage culvert near Watford in Northamptonshire.
The set-up was uncovered on 28 November when National Highways staff entered the culvert — a tunnel that channels water beneath the motorway — and found the entrance boarded up to hide rows of cannabis plants. They immediately alerted Northamptonshire Police.
Officers said the culvert stretched beneath both carriageways, providing a remote but concealed space for those running the illicit grow.
Torrential rain made dismantling the site more hazardous, but the Daventry Neighbourhood Policing Team were supported by a nearby landowner who supplied vehicles and trailers to help remove equipment from the tunnel.
Inspector Jonathan Davis-Lyons said the location was “one of the most unusual” ever used for a cannabis grow and showed “the length criminals will go to produce this high-value commodity”.
He said officers found extensive shelving to keep plants above water, along with diverted power for lighting and other equipment.
Sergeant Lewis Judd, who is leading the investigation, said the remote site made access difficult. With the nearest road around a mile away, the team relied on the farmer’s assistance to reach the culvert and shut the operation down.
No arrests have yet been made, and police are appealing for anyone with information that could help identify those responsible.
