Pro-cannabis rally planned for Peterborough's Central Park

The sit-down protest is being organised by group IronLungs UK after 11-year-old Billy Caldwell from Northern Ireland, who suffers with epilepsy, was prescribed cannabis oil on the NHS - believed to be the first time this has happened.

Matt Chapman (30) of London Road, who is organising the rally, said medical marijuana can cure cancer and should be used widely. He also claimed that using the drug relieves the pain he suffers with from Crohn’s disease and Barrett’s oesophagus.

Matt said: “Cannabis saves lives, the NHS kills lives. That’s what our slogan is. In 20 states in America it shrinks tumours.”

The online event page for the rally on Monday, July 10, from 1pm, states: “Smoking cannabis is not advisable but do as you wish. This is a rally, you have your right.”

Smoking cannabis is illegal in the UK, but Matt said: “We are there to highlight cannabis and get it legalised. If people want to smoke it let them smoke it. I openly walk around the streets smoking a joint.

“There’s a big stigma with it, but you will be surprised how many people smoke cannabis.” Matt added that the rally will be peaceful and that the park will be cleaned up afterwards.

A Peterborough City Council spokeswoman said the authority is aware of the rally but that it is up to the police whether to sanction it.

Cambridgeshire police said it will assess the event in the coming weeks and speak to the organiser about what might be required on the day.

A spokesperson said: “While we welcome peaceful demonstrations in the city we would remind people that using, carrying, making or selling cannabis or any drugs or psychoactive substances is illegal and those caught could be arrested and prosecuted.”

The Medicines and Healthcare products Regulatory Agency, a government agency, said licensed products containing cannabidiol can be prescribed by a GP.