The low price indicates there is a huge supply of the drug. This is supported by the record seizures of heroin by customs officials. In 1997, they confiscated 1.8 tonnes of heroin worth £145m - a 300% rise over the previous year.

In the first three months of 1998 alone, customs and police captured heroin with a value of £150m.

The UK's drugs czar Keith Hellawell warns of a heroin epidemic: "Dealers like it because people become addicted quicker and their reliance is secured.

Keith Hellawell says cheaper drugs benefit dealers

Aids fear

There are about 40,000 registered heroin addicts in the UK, but Mr Hellawell believes the figure is probably nearer 160,000.

Dick Kellaway from the Customs National Investigation Service says most of the heroin seized was designed for smoking rather than injecting because of the fear of Aids.

"Heroin use in Britain has traditionally been confined to a hard core of 'career' addicts.

"It is worrying to see the upward trend and to hear, albeit not widely confirmed, that some dealers are offering heroin to young people who are in the market for drugs such as cannabis and ecstasy."

Injecting has become unfashionable

Mr Hellawell agrees: "It becomes more attractive to the young user when the pusher says, 'I'm not going to sell you stuff that gives you Aids. Have this stuff to smoke, it gives you a better hit'."

A fifth of all people arrested in Britain are on heroin. A recent study has shown that 700 addicts committed 70,000 crimes within a three-month period to fund their habit. The researchers believe the average addict steals goods worth more than £43,000 each year.

Most of the heroin seized by customs comes through Turkey. It has been produced from the opium grown in the fields of Afghanistan and Pakistan. Officials say the drug gangs see Britain as both market and warehouse for drugs destined for Europe and the United States.

One lorry stopped in 1997 at London's Blackwall Tunnel was carrying 100kg of heroin, worth £8m.

Policy "failure"

Labour MP Paul Flynn, vice-chairman of the Commons Drugs Misuse group, says the figures show the "abject failure" of Britain's drug policies.

"Dutch de-criminalisation has cut hard drugs use. Here, prohibition has increased drug use. In the UK, heroin deaths rose from 52 to 186 in the most recent three-year period."

"The drug czar's policies against the tidal wave of drugs will be as successful as King Canute's. The government should recognise failure, face a national debate through a Royal Commission and pursue radical reforms that have worked elsewhere."