Derbyshire, Dorset and Surrey police forces are said to be willing to turn a blind eye to those who grow cannabis, a Class B drug, for personal use – in order to focus on more serious crime.

The move follows a similar one by the Durham Constabulary, which announced last week it would only pursue people growing the drug if there was a specific complaint or their use was blatant.

While the government has not officially decriminalized the drug, forces appear to be becoming increasingly relaxed about its use and more inclined to warn offenders than charge them.

There may also be economic constraints, given the effects of austerity on UK police forces.

Kevin Hurley and Martyn Underhill, the chief constables for Surrey and Dorset, respectively, took similar positions, with Hurley telling the Daily Mail: “On the list of priorities, cannabis moves a long way down the chain.”

Steve Rolles, policy analyst for drug reform campaign group Transform, told the Telegraph: “There are other police authorities that are doing similar things but they are not shouting about it.”

He echoed the view that funding was driving the shift in policing methods.

“As police forces face increasing cuts they will have to make these decisions. I do not see this as an ideological position but a resource issue, directing their limited resources towards where they are needed,” he said.

Alongside the impact of austerity there is a growing movement not just to decriminalize the drug but to legalize it.

As of Sunday, a petition for the full legalization of marijuana in the UK had collected more than 130,000 signatures in just four days, which means lawmakers must now consider debating it in parliament or at least officially respond to the query.

The electronic petition calls for the legalization of the production, sale and use of cannabis and currently has close to 135,000 signatures since its launch on July 21.

“Legalizing cannabis could bring in £900 million ($1.396 billion) in taxes every year, save £400 million ($620 million) on policing cannabis and create over 10,000 new jobs,” says the appeal, which appears on the government’s petitions website.

The campaign also argues the drug is “safer than alcohol,” has been used by mankind for over 4,000 years, and was only outlawed in the UK in 1925.