People are being urged to help create a cannabis odour map to trace how far the smell of legal plants waft across the region during harvesting.

The odour mapping has been set up following complaints from across Norfolk and Cambridgeshire about the smell coming from the first harvest at the British Sugar plant at Wissington, near Downham Market.

Fenland District Council has launched the mapping in response after the plan switched from growing tomatoes to cannabis plants for medicinal purposes.

An FDC spokesman said; “Our Environmental Health team continues to investigate the issue with neighbouring authorities, with reports of the smell continuing to come in from across Cambridgeshire and Norfolk.

“We need the public’s help to assist with ‘odour mapping’ to pinpoint its source.

“When reporting the cannabis odour, please tell us the postcode/location of the smell - where you were when you smelt it, the date and time you smelt it, and, if possible, the wind direction at the time.”

FDC have set up an odour mapping post on its Facebook page and has a link for the public to report to on its website.

People have posted about smelling cannabis across the Fens, Norfolk and Suffolk in towns including March, Wisbech, Murrow, Littleport, Thetford and Marham.

An environmental specialist and odour consultant were brought in to investigate and South West Norfolk MP Liz Truss met with parish councillors and British Sugar bosses to raise the issue.

She said:‘The recent harvest of the specialist crop was the first one to come from Cornerways Nursery, near Wissington and with the process taking about four to five weeks, there is the potential for strong smells to linger for quite a few days.

“British Sugar have assured me that they do not want to create any problems for local residents.

“I think everyone recognises the importance of the work done at the factory but it should not impact on surrounding towns and villages.”

The plants are used in Epidiolex for childhood epilepsy.

A British Sugar spokeswoman said: “We have been unable to identify a source which may be contributing to off-site odours.”

Report cannabis smells and help them with regional odour mapping on this link.