I am instinctively hostile to the risky use of drugs, both legal and illegal. In fact, I share common ground with many of the people who don’t want our drug laws to be reformed, for we can all unite on the importance of reducing harm to young people.

Yet it is exactly this fear of harm that makes me a supporter of reform to our cannabis laws. For if we take harm seriously and examine the evidence, two things become clear.

First, our current laws on cannabis are not working. Official figures show that around three million people used cannabis in the year ending April 2018. High potency skunk (which, when used heavily, is closely associated with mental health problems) now makes up 94 per cent of the street market in London.

Violence associated with the illegal drugs trade has reached record levels — and teenagers too often find themselves on the frontline. Meanwhile, we hand billions of pounds to organised crime on a plate.

Secondly, stepping up the war on drugs is not the solution. A 2014 Home Office study showed that there is no clear relationship between tough drugs enforcement and levels of drugs use.

People are going to keep using cannabis, so fresh thinking is needed. If we legalise it in a careful way, by strictly regulating the cannabis market, including a cap on potency, we can protect young people from the most damaging strains of the drug. We can take supply out of the hands of the criminal market. And we can treat cannabis use as a health issue, not a criminal one.

Following the evidence is important, which is why I welcome the Evening Standard’s special investigation into cannabis reform. It will inject fresh energy into this debate.

And it couldn’t come at a more timely moment — in the Conservative Party leadership race, we’ve just had the most glaring example of the hypocrisy which pervades discussion of cannabis.

For so many politicians, cannabis use is merely an embarrassing confession from their past. But if you’re someone who’s been charged for cannabis possession, whose career has been ruined by a prosecution or even a caution, it’s a completely different story.

And if you’re a person of colour and from a poorer part of town you are far more likely to face punishment. For instance, black people make up less than four per cent of the population, yet they account for a quarter of those convicted of cannabis possession. There is an overwhelming sense of unequal (and unnecessary) treatment, and of injustice.

The solution is to take this issue out of the hands of criminals and the courts. That’s what they’ve done in Canada, where a legal and regulated market was introduced last year. They engaged with the evidence and were honest about the failings of the system they had, and that generated the political willpower to make a change. Now it’s our turn.