Britain is facing an epidemic of hepatitis C, with the number of cases likely to be double that of official estimates, The Independent has learnt.

Britain is facing an epidemic of hepatitis C, with the number of cases likely to be double that of official estimates, The Independent has learnt.

More than 500,000 people in the UK may be infected with the virus, a study by doctors at Southampton University has found. Experts said that the government figure of 250,000 cases was a "gross underestimate", and warned that the NHS was facing a time-bomb of potentially fatal liver disease as a result of ministerial failures to tackle the problem.

Professor William Rosenberg, a liver disease expert at Southampton University, said: "We are seeing twice the number of cases that we would expect if the official estimates were right.

"The tragedy is that if nothing is done, in the next 10 or 20 years we are going to end up with tens of thousands of people needing liver transplants, with hospital wards overflowing with patients with end-stage, untreatable disease and liver cancer. The cost to the NHS and public health could be absolutely disastrous."

Hepatitis C is a blood-borne virus that causes inflammation and damage to the liver.

The majority of people experience no symptoms for many years, but an estimated 30 per cent of patients will develop fatal cirrhosis of the liver if the disease is left untreated for more than 20 years. New drugs for hepatitis C have up to a 90 per cent cure rate, yet less than 1 per cent of infected people have access to them.

Government figures, supplied by the Health Protection Agency (HPA) and based on random testing of blood samples in hospitals, have assumed that 250,000 people in the UK are infected with the disease.

But experts say that the HPA estimates do not accurately reflect the large number of people who would be considered at "high risk" of infection.

The main causes of infection are through intravenous drug use, dirty tattooing kits and contaminated blood products prior to 1991, when screening was introduced.

Professor Rosenberg said: "The problem is that many people look at these risks and don't think it applies to them. But there is a huge cohort of people who 20 or 30 years ago may have dabbled in drugs, even just once at a party, who could be infected.

"They are judges, businessmen, lawyers. They are the ones who could have had the virus for 20 or 30 years now and could soon start developing end-stage liver disease."

Professor Rosenberg said that because the HPA estimate is based solely on random testing of blood samples in hospitals, it is not representative of the scale of high-risk groups.

Testing of hospital blood samples does not take into account the high rates of infection among drug users, who tend not to use health services, as well as ignoring the fact that the majority of those infected are otherwise healthy and often have no need to visit a hospital.

The statistical modelling by the Southampton University team used new estimates of high-risk groups, including current drug users, prisoners and people who have previously experimented with intravenous drugs. The figure tallies with the most comprehensive study of hepatitis C prevalence, carried out in France, which estimated that about 1.2 per cent of the general population was infected, compared with the 0.4 per cent assumed by the HPA.

Out of the estimated 500,000 infections, just 60,000 people have been diagnosed and only 3,000 are receiving treatment.

Almost 6,000 new cases are diagnosed each year, and last year the Government launched a hepatitis C strategy to tackle the issue and raise public awareness of the virus.

Charles Gore, chief executive of the Hepatitis C Trust, said: "There is a firestorm that is starting to brew in hepatitis C and nothing is being done about it. The Government promised a big campaign but we have seen very little action. I am extremely disappointed, and very concerned that we are going to be engulfed by an epidemic of liver disease very soon."

The Department of Health insisted yesterday that it was taking the issue seriously.

A spokeswoman said: "Our hepatitis C awareness-raising campaigns for health professionals and the public are in their early stages.

"We will evaluate progress and review whether the scope of the campaign needs to be extended.

"Current information suggests that the current level of chronic hepatitis C infection is around 0.4 per cent of the population, or about 200,000 people. This estimate has been made by the Health Protection Agency, which provides authoritative advice on infectious diseases and co-ordinates national surveillance".

Public health experts are concerned that the stigma surrounding hepatitis C and a widespread assumption that it is a "low-life" disease discourage people from seeking a test. They want a campaign on the scale of the HIV/Aids health warnings in the 1980s to publicise the threat.