As I stood with a rolled up bank note in my hand, staring down at the thin line of white powder I was about to snort, I thought back to the innocent shopping trip earlier that day which had led to all this.
I should emphasise now that taking drugs does not constitute my usual type of weekend activity, I assure you. I am, after all a doctor and, having seen first hand the devastation that illegal drugs cause, I'd never advocate their use.
The drug I was about to do, though, wasn't illegal. I'd broken no law when I bought it and I wasn't breaking any by taking it.
Yet, this controversial substance is now the drug of choice for many young people in the UK.
I had been in central London buying a birthday card when I noticed a row of small packets on the counter by the till. They caught my eye and as I waited to pay I absentmindedly picked one of them up. On the inside was stapled a small transparent bag with a white powder inside. In tiny letters on the front it said: 'water soluble all purpose plant feed'.
For a brief moment I was genuinely puzzled as to why a gift shop was selling plant food.
Then I suddenly realised, this wasn't plant food in the conventional, Baby Bio, sense. This was mephedrone, sometimes known as "meow meow" or "plant food".
It's not to be confused with methadone - a heroin substitute, which is a carefully controlled, prescription-only medication.
Instead, it's a "legal high" that has become increasingly popular as a cheap and easy alternative to illegal street drugs such as ecstasy or cocaine.
I first heard about the drug last summer. At first, it was patients who incidentally reported taking it when I was seeing them in A&E and I asked about their drug use.
They all raved about it. And here, standing in a shop just a few hundred yards from London's Oxford Street on a crisp, spring afternoon, I'd stumbled across it for myself.
Impulsively I bought some. Back at home, I debated whether I should actually try it. Surely it can't be that bad if I can buy it in a shop, I reasoned to myself. But more than anything I felt I had to know what it was that so many of my patients were telling me they were taking each weekend and whose experiences were in such stark contrast to the media scare stories.
I reasoned that by trying it I might understand better the drug's appeal and decide for myself if the government is right in pushing ahead to make it illegal. My prohibition on taking drugs up until this point had been that they were illegal.
I think that people should be free to make choices about their lives and that, providing they are aware of the consequences, this includes doing things that might damage their health. I am not a complete puritan - I smoke and drink.
But my problem with illegal drugs is the human suffering that surrounds this market. They ruin lives and communities and that's not something I want to buy into.
But this was different. There was a veneer of respectability about buying this drug and it was this, along with the complete ease with which I obtained it, that worried me afterwards. I didn't need a dealer or contacts. I'd wandered into a shop and picked it up as though it were a pair of novelty socks. This drug isn't even like alcohol or cigarettes, which have age restrictions on their use. Literally anyone can get hold of it and yet it is so new we know next to nothing about its long-term effects.
What particularly worries me is protecting the young, because their concept of risk is still developing and their ability to moderate their use of substances is often poor. It's ludicrous that teenagers who the law says cannot even buy a goldfish are able to obtain this stuff perfectly legally and that parents and schools have no official powers to intercede. Something does have to be done.
For a multitude of reasons, people like to use intoxicants. What is becoming increasingly apparent is that for some, the main legally sanctioned one - alcohol - is not adequate. Alcohol is a depressant and there are groups of people who want to use a stimulant instead. While this market exists, they will either use illegal drugs like ecstasy or cocaine, or seek 'legal' alternatives, which have the added bonus of being cheaper and purer and not carrying the risk of imprisonment.
Making mephedrone illegal will stop many of the people I know using it. It will also remove the implicit suggestion that because it's legal it must be safe and will stop it being so readily available to teenagers.
But I also know that simply making something illegal will not stop it being used by everyone, or indeed eradicate the need that people have to take substances that temporarily alter their experience of the world and intoxicate them.
I do not take drug use lightly. But if we want to ensure that people are kept as safe as possible, then is banning it the best solution?
As yet another expert - Eric Carlin - resigns from the government drugs advisory board amid claims that not enough is being done to actually help those using drugs and reduce harm particularly to young people, do our current policies on tackling drug use really work?
The reality is that, as soon as mephedrone is banned, it's only a matter of time before another substance will take its place. Then what?
After yet more tragic deaths, yet more legislation will be rushed through and this new substance will be banned and the whole sorry fiasco will start again.
The rise of the internet has meant that it is all too easy to take a basic chemical structure, make a few alterations, email the formula off to an overseas laboratory and, in no time, a new drug is born. The authorities will always be one step behind.
There may come a point in the future where we tire of this cat-andmouse game and accept there is a need for a legally sanctioned stimulant.
Perhaps it will be safer in the long term to restrict the use of these substances to adults and license their sale and enable information to be gathered about their side effects, longterm health implications, dosing and risk minimisation, just as we have done with alcohol and cigarettes.
It will mean that people aren't pushed into breaking the law, that quality can be ensured and perhaps even sales of other, illegal drugs, will fall, just as has happened with ecstasy and cocaine since mephedrone became available.
It will also quash the drive for creating new legal highs which minors can get their hands on.
While ministers like to appear to be tough on drugs and to respond quickly to public concerns, perhaps what is needed if we're going to ensure that people's health is best protected is to step back and think carefully.
I can understand now why people might be attracted to mephedrone - I felt euphoric, energised and elated after I took it.
But I can equally understand the concerns that the drug attracts. In an ideal world people wouldn't feel the need to use drugs to enjoy themselves, but we have to be practical because people's lives are at stake.
We desperately need a sensible, adult debate about this, because my concern is that knee-jerk reactions won't actually solve the problem.
They might even make it worse.
25 The number of deaths linked to mephedrone in England and Wales. A recent drugs poll showed 41.7% of clubbers had taken it
£4-£30 The cost of 1g of mephedrone. The average profit margin on 1kg imported from China if sold at £10 a gram is £7,500
By Max Pemberton
April 5, 2010
Meow is legal so I tried it. But will banning every new drug really fix drug problem?