Unpublished research has suggested high levels of use of a chemically modified form of amphetamine amongst the gay community, BBC News has learned.
Drug dealers have been selling methamphetamine as crack cocaine
Research by a team at the City University London suggested that one in five gay men who were surveyed were using methamphetamine.
Drugs workers and some police officers believe that methamphetamine may be about to become more widely abused.
In the US the drug has been likened to a cheap form of crack.
Methamphetamine is a chemical variant of amphetamine with much more powerful effects.
Link to unsafe sex
Its recreational use can quickly lead to a physically damaging and chaotic lifestyle, and has been associated with increased levels of unprotected sex among gay men.
Some drug dealers have apparently been trying to sell the drug, which is known as crystal or tina, as crack cocaine in an attempt to create a wider market, BBC correspondent Rory MacLean said.
The research among gay men in gyms shows a high and steady usage.
"Overall we think the figure is somewhere between 10 and 20% of gay men in London are using the drug," said Professor Jonathon Elford.
"Certainly it is something that health promotion and drug workers need to be aware of, it should be included in a broad harm reduction and drug programme."
Spread of drug
However, the drug is spreading beyond the gay community.
"We're getting reports of methamphetamine being used in the clubbing scene, particularly the gay clubbing scene, and also reports of methamphetamine in a really basic form being sold as crack on the streets," said Aidan Gray of Coca, an organisation which trains drug workers.
PC Andy Hewlett, who works in London with the gay community, says the time is right for awareness campaigns.
"There is a risk of doing it too early and enticing people into using it because all of a sudden there is a new drug out there which is very connected to sexual activity and people wish to try that.
"At what point do you start [campaigns] because people are being affected by it, their lives are becoming chaotic? We think the time is actually now."
Former user Alexander said the drug "literally rewires your brain".
"Everything in your world when you're on crystal revolves around tina, which is the nickname it has.
'Like a virus'
"You are literally controlled by her. You become almost a robot or, as I've seen in a friend of mine who's been a crystal addict for the last five years, you become a slave to that drug."
Gary Lee set up the website Lifeormeth.com after seeing what had happened in the United States as methamphetamine spread.
"I see crystal meth as a virus.
"Like any virus that is not contained it will just spread and spread.
"It will engulf the mainstream community too, in much the same it has happened in mainstream America."
What is your reaction to the findings? What can be done to stop the spread of methamphetamine abuse?
This debate is now closed. Thank you for your comments.
I agree with Mr Damaged that the percentages mentioned are far from giving a realistic picture of the abuse of this drug amongst gay men as a whole. Tina is a growing problem true, but GHB is widespread and far more dangerous. However, it must be said that Tina is addictive and people should be aware that this kind of drug can ruin their lives. Don't be a victim to Crystal Meth! It's ugly man!
Can we note that this is unpublished research and based on people they've met in gay gyms - far from representative if not distorting. Crystal is horrendous but we're far from where this report suggests - the real crisis is GHB.
Mr Damaged, London, UK
Methamphetamine manufacture requires some very specific chemicals and a very dangerous production process. If it is, as I suspect, being manufactured in the UK then the chemical companies could be recruited to watch over various chemicals needed to produce the drug. I appreciate that manufacturers would shop around buying different components from different suppliers, but if one chemical was controlled, it would be possible to curb the drugs production.
Mike Eyre, Brough, E Yorks