A new group looking at whether to decriminalise cannabis in the UK has been set up by London mayor Sadiq Khan.
Former justice secretary Lord Charlie Falconer QC will chair the first ever London Drugs Commission.
Mr Khan described his visit to a cannabis dispensary in the US state of California as “fascinating”.
But Home Secretary Priti Patel said the mayor of London was wasting his time as he “has no powers to legalise drugs”.
Labour said in a statement the party does not support changing the law on drugs.
The main drug offence recorded in England and Wales last year was “possession of cannabis”
Cannabis is currently classed as a class B drug in the UK, with a maximum sentence of five years in prison for possession.
In 1996, marijuana became medicinally available in California and 20 years later you can possess, use, grow and gift the narcotic.
In 2018, you could buy and sell it recreationally for the first time.
Mr Khan said: “We need to have an honest, open conversation about the evidence in relation to the history of cannabis and our laws in the UK and our experience of the health consequences in relation to crime and the community.
“The best way to do that will be with the drugs commission we’ve now set up.
“You can hear from the experts, that’s one thing, but seeing it for yourself … hearing from those who cultivate and grow this plant has been fascinating.”
Once it has completed its work, the commission will make recommendations to City Hall, the government, the police, the criminal justice system and public health services.
‘Tear apart families’
University College London will provide research and analysis on the impact of any policy changes.
Reacting to Mr Khan’s announcement Ms Patel tweeted that the mayor’s time “would be better spent focusing on knife and drug crime in London”.
“The mayor has no powers to legalise drugs. They ruin communities, tear apart families and destroy lives,” she said.
Mr Khan’s own party also distanced itself from the mayor’s comments, saying: “Drugs policy is not devolved to mayors and under Labour would continue to be set by national government.”
On Wednesday, Mr Khan met with Los Angeles mayor Eric Garcetti, and visited a cannabis dispensary and farm in the city to see what lessons could be learned in the UK in responding to the challenges of drugs.
About 2.6 million people in the UK used cannabis in the year to March 2020 when the pandemic struck, data from the Office for National Statistics shows.
As well as being justice secretary, Lord Falconer was a minister at the transport department, and then the Home Office, during the Tony Blair era.
He went on to become shadow justice secretary under the acting leadership of Harriet Harman, a role he kept under Jeremy Corbyn.
Speaking about the visit, Steve Rolles, of the Transform Drug Policy Foundation, told BBC Radio London the capital needed to learn from countries like Mexico and Uruguay which have decriminalised cannabis.
He said: “Clearly as the mayor has pointed out, our cannabis policy is not working.
“It is not deterring youths and we can always smell it off them. It is criminalising lots of people – particularly young black males – and it costs the criminal system a lot of money.