Last week the Global Commission on Drug Policy said the ‘war on drugs’ has failed.

Making them illegal causes more problems than it solves- criminals control supply resulting in inevitable violence and illicit activities.

Demand will not go away, they say, and the time has come to ‘end the criminalization, marginalization and stigmatization of people who use drugs but who do no harm to others’.

The drug khat, which is chewed like tobacco, provides an interesting case. Legal in the UK, it is now becoming associated with problems among West African communities in Hillingdon, who use it as part of their culture.

With around seven tonnes arriving in Heathrow every week, Hillingdon is susceptible to khat use, particularly as the plants and their potency are rendered useless after 48 hours. Proximity to its arrival is a factor in who uses it and where it goes.

This has prompted Hillingdon Council to produce the Hillingdon Khat Report, detailing its effects on the community.

In light of the Global Commission’s recommendations, would a ban be the right thing to do? Given that it is legal, has khat not been an unintentional experiment in legalisation?

The issue is complicated by a few factors.

First, there are the effects it has on the individual. It is often described as a ‘mild stimulant’, increasing talkativeness and alertness. Others say it can induce paranoia, irritability and dependence.

Then there are the social effects. Hillingdon Council has identified so-called 'khat dens'. Since it isn't a controlled substance, some users entering the dens may be children.

Also, some Somali men seem to be over-indulging in the drug on a daily basis, resulting in them staying at home doing nothing.

Would banning khat make these effects better or worse? It is difficult to say given its tentative status as a 'mild stimulant'.

With other drugs, the allure is clear: the effects are powerful and can quickly form dependency.

Moreover, in parts of West Africa, khat is treated in the same way we have a 'coffee culture'.

I went to Hayes, in Hillingdon, to find out from khat users and the Somali community if they think it should remain legal. I also went to see the effects for myself.

Ahmed, a Somali who has been in the UK since 2002, took me to meet khat chewers. He would like to see a ban.

"It makes people crazy, and they just sit around doing nothing, talking rubbish. It's not a nice drug," he said.

He also told me about how in Somalia it is usually chewed in moderation. But people here have started to use it in excess.

"It's all they do sometimes, and they can claim benefit, so they don't have to work, then they just chew khat," he said.

When I met Mohammad at the back door of a house down an alleyway he immediately became guarded on the subject, despite its legality.

He took my number and insisted he would call me. As he ushered us away I could hear animated conversation from the house. As we walked away, four Somalis chased after us.

They made it clear to say the least, to Ahmed, that he shouldn't have brought me there. They were wide-eyed, aggressive, and reviled me for coming to the house 'without permission'.

It's difficult to say how much this reaction was down to khat's side-effect of paranoia Ahmed told me about. It may have been due to taking other drugs, or involvement in other drugs at the house. But it did seem strange that mention of this legal high alone caused such a hostile response.

If it was simply consumption of khat, they had chewed enough to experience its ugly side.

What did emerge though was that people seem to either abstain, like Ahmed, or they use it to excess, as a lifestyle choice.

Abuke Awale is an ex-addict and anti-khat campaigner who wants a straight-forward ban. While he was on the drug he says he was careless and paranoid. He was also stabbed five times.

He describes users' dependence on 'warming up'. They have a psychological dependence on chewing khat to get motivated.

"That's when the trouble starts," he explained.

"It’s the biggest barrier to integration – people stay in their own world while they’re on it. It's stronger than alcohol," he said.

Banning it, he says, would protect the young and vulnerable.

"The community would benefit, lives would improve," he added.

Danny Kushlick, founder of Transform Drug Policy Foundation, is one of those questioning a ban.

"It would be the stupidest thing you could do, it would be a disaster," he said.

"If they did ban it, it would make matters worse."

He admits there are problems in West African communities, and they are sometimes exacerbated by khat. An illegal market would be created, leaving khat in the hands of criminals.

He thinks the answer may be to regulate khat in a similar way to alcohol rather than ban it outright.

Indeed this was also the recommendation of the Hillingdon khat report. They see regulation as the best compromise, having the advantages of age restrictions, suitable retailing premises and avoiding stigmatisation.

Mr Awale disagrees. He says that by remaining legal, or even going under regulation, it is sending the wrong message that khat is not harmful.

"If I knew at the time it was a drug I wouldn’t have done it," he said.

He added: "I'm not saying everything would be fine with a ban, but it would send a clear message.

"Regulation would only consume taxpayers' money and resources."

Mr Awale also pointed out, contrary to claims that khat would go underground, it would be difficult to smuggle. The plants have to be brought in whole, so would be easily detectable.

And with a ban in the UK, it wouldn't be shipped on- the UK is currently a stepping stone, said Mr Awale, because there is a time-limit on khat's effectiveness from the time it's picked.

Although there is evidence khat is powerful enough that people will smuggle it – Norwegian Customs seized 10 tonnes of khat in 2010 – eliminating the UK's role in the process may dry up the supply.

Graham Hawkes, who works with Somali communities through Hillingdon LINk, points to the ash cloud last year, which resulted in there being no khat available.

"If they stop taking it, there is instant recovery. During the ash cloud there was no khat. It cleared the mind, and there was no paranoia," he said.

He has surveyed the leaders of the Somali community, and has seen it affecting families and schooling.

Nevertheless, he does not think a ban is the way forward.

"Making it illegal would have knock-on effects – the price would be driven up for a start. This may make the situation worse," he said.

Like Mr Kushlick and Hillingdon Council, he sees regulation and licensing as the way forward.

With khat’s idiosyncrasies, particularly the time-limit on its effectiveness, its legal status is not an entirely sound experiment for all drugs.

But in khat’s individual case, it does seem some kind of control is needed to alleviate its downside.

The cost of regulation will be unpopular and its semi-legal presence in the UK will tempt smugglers.

However, in clearing up the khat dens and encouraging moderation, it is probably the lesser of two evils.