Britain's most senior police officer has described the legalisation of cannabis in Canada and parts of the US as "interesting experiments" that should be watched.

Met Police Commissioner Cressida Dick gave her views on legalisation of the drug during an interview on BBC Radio London's Drive Time show after being asked by a listener.

She said the debate around the subject was "complex" and believed if the UK was to legalise drugs immediately, it could lead to a variety of health problems.

However, speaking to radio show host Eddie Nestor on Monday, Dame Cressida said: "I think it is worth looking at what is happening in Canada and parts of the United States, albeit we have to recognise culturally that is very different.

Cannabis goes on sale in Canada - In pictures 11 show all Cannabis goes on sale in Canada - In pictures 1/11 A depiction of a cannabis bud drops from the ceiling at Leafly's countdown party in Toronto AP 2/11 Canadian flag with Cannabis leaf AFP/Getty Images 3/11 Customers line up outside the Natural Vibe store after legal recreational marijuana went on sale in Canada REUTERS 4/11 A man plays a song as customers line up outside the Natural Vibe store after legal recreational marijuana went on sale in St John's, Newfoundland and Labrador, Canada REUTERS 5/11 A customer looks at cannabis on display after legal recreational marijuana went on sale at a Tweed retail store in St John's, Newfoundland and Labrador, Canad REUTERS 6/11 Cannabis is seen on display at a Tweed retail store after legal recreational marijuana went on sale in St John's, Newfoundland and Labrador, Canada Reuters 7/11 Canopy Growth CEO Bruce Linton applauds after handing Ian Power and Nikki Rose, who were first in line to purchase the first legal recreational marijuana after midnight Reuters 8/11 Customers line up to purchase the first legal recreational marijuana that will go on sale after midnight at a Tweed retail store in St John's, Newfoundland and Labrador, Canada Reuters 9/11 An estimated 400 people were in line to purchase cannabis at the Tweed retail store on Water Street, in St. John's, Newfoundland and Labrador, when it became legal after midnigh AP 10/11 People smoke cannabis on the street in Toronto AP 11/11 People smoke cannabis on the street in Toronto AP 1/11 A depiction of a cannabis bud drops from the ceiling at Leafly's countdown party in Toronto AP 2/11 Canadian flag with Cannabis leaf AFP/Getty Images 3/11 Customers line up outside the Natural Vibe store after legal recreational marijuana went on sale in Canada REUTERS 4/11 A man plays a song as customers line up outside the Natural Vibe store after legal recreational marijuana went on sale in St John's, Newfoundland and Labrador, Canada REUTERS 5/11 A customer looks at cannabis on display after legal recreational marijuana went on sale at a Tweed retail store in St John's, Newfoundland and Labrador, Canad REUTERS 6/11 Cannabis is seen on display at a Tweed retail store after legal recreational marijuana went on sale in St John's, Newfoundland and Labrador, Canada Reuters 7/11 Canopy Growth CEO Bruce Linton applauds after handing Ian Power and Nikki Rose, who were first in line to purchase the first legal recreational marijuana after midnight Reuters 8/11 Customers line up to purchase the first legal recreational marijuana that will go on sale after midnight at a Tweed retail store in St John's, Newfoundland and Labrador, Canada Reuters 9/11 An estimated 400 people were in line to purchase cannabis at the Tweed retail store on Water Street, in St. John's, Newfoundland and Labrador, when it became legal after midnigh AP 10/11 People smoke cannabis on the street in Toronto AP 11/11 People smoke cannabis on the street in Toronto AP

"As a citizen, my own view is almost certainly if we were to legalise immediately here, we would come up with all kinds of problems that would not help, not least the health issues that would be associated."

Earlier this year, the Evening Standard launched an investigation into reforming the laws on cannabis. It found that 63 per cent of Londoners back legalisation for adult recreational use.

Growing, buying and possessing cannabis was made legal in Canada on October 17, while nine states in the USA have legalised recreational sales of the drug. It is illegal for recreational use in the UK, although it can be prescribed for medicinal purposes.

Dame Cressida said she "accepts" there is a lot of cannabis use in London and that people in possession of small amounts will not be "locked up" for it, adding: "I am not suggesting they should be in the first instance."

"My own view is that we should watch what happens in the states and Canada. It is an interesting set of experiments.

"My concern is, I’m not a health professional, but you see what is happening with skunk and some of the damage done to people with mental health issues, is absolutely huge.

"The organised crime groups, in my view, would come in and cause problems in different markets and start selling different things to people.

"Let's see though what happens."