A top university professor says people should legally be allowed to grow their own cannabis.

Drug expert Alex Stevens claims anyone aged over 18 should have the right to cultivate up to six plants each.

He made the comments after the release this week of an independent report by the UK Drug Policy Commission.

The controversial report says possession of small amounts of controlled drugs should no longer be a criminal offence.

It came as figures showed more than 300 cannabis production offences were recorded each week across the country.

Professor Stevens, an expert in criminal justice at the University of Kent’s School of Social Policy, Sociology and Social Research, said: “Those left with a criminal record for possession of a small quantity of cannabis will find the criminal record does far more damage than the drug did.

“The first stage in reforming drug policy that is actually harmful would be to decriminalise possession.

"Anyone should be able to grow six plants at any one time. We are spending too much on drug policies that cause harm, or have little evidence of preventing harm.”

But Canterbury MP Julian Brazier, a firm opponent of any relaxation of drug policy, slammed the suggestion.

He said: “First offences are not usually severely punished anyway. Any change in law would send completely the wrong signals.

“Cannabis today is not the same, so I’m told, as it was 30 years ago when my contemporaries were taking it.

"The reason why we are having such a massive rise in mental health issues among the young is in no small part down to the widespread use of drugs.”

But dad-of-two Professor Stevens hit back. He said: “The links between cannabis and mental illness are far less clear cut than most people believe.

"Besides, a regulated market would mean people would have access to less strong cannabis. And many who move on to harder drugs do so after their dealer offers them something else.

“The UKDPC’s recommendations to review the punishments for drug supply and to harmonise regulation of alcohol, tobacco and other drugs are sensible and timely.

“I wouldn’t want my children to be taking cannabis before they are 18 any more than I would want them to be drinking.

"But the fact is that government policy is not going to prevent that - that is down to how you talk about things as a parent.”