Surge in skunk adds to pressure for reversal of cannabis downgrading

Three-quarters of the cannabis in circulation is the potent "skunk" variety blamed for causing mental illness, research for the Home Office has disclosed.

The soaring popularity of skunk, which is – on average – three times more powerful than cannabis resin and herbal cannabis, emerged as the Government considers whether to reverse the downgrading of the drug from a class B to class C substance. The increase, alongside mounting evidence of a link between regular cannabis use and psychosis, further raises the likelihood that Jacqui Smith, the Home Secretary, will back the reversal.

Skunk now accounts for 70 to 80 per cent of the cannabis taken in England and Wales, according to an analysis of drug samples seized in recent months. That compared with just 15 per cent in 2002. The drug was virtually unknown in Britain in the early 1990s.

Cannabis resin represents 20 per cent of the market, while herbal cannabis has almost disappeared. Les King, an adviser to the Home Office Scientific Development Branch, told a public hearing of the Advisory Council on the Misuse of Drugs that skunk contained 14 per cent THC, the ingredient that produces the "high", while herbal cannabis had a 5 per cent content. But he said: "It's the same as saying wine is twice as strong as beer. It is not only what you drink but how much.

"Regular statements are made that cannabis is ten, 20 times stronger than it used to be. It is misleading and it is wrong."

The Association of Chief Police Officers and magistrates told the committee, whose conclusions will be handed to Ms Smith in April, that they want the drug reclassified.