Drug users who inject are the main reason for a surge in the number of cases of hepatitis B, public health officials have said.

Figures from the Public Health Laboratory Service (PHLS) show cases have risen by almost a third since 1998 - up from 652 to 855.

Drug injecting was known to be the most likely cause in 46% of infections.

Health officials have called for the government to invest in a vaccination programme for drug users to prevent the disease spreading out of control.

Liver disease

Hepatitis B can damage the liver, but it can also be carried for years with no visible symptoms and it is usually expelled from the body within 13 weeks of infection.

It is carried in body fluid and can be transmitted through sharing needles, blood transplants and sex.

It is thought that around 50,000 people in the UK may carry the virus.

Some will only go on to show flu-like symptoms, but in rare cases the virus, if left untreated, can cause liver failure.

However the disease is 10 times more infectious than Aids, and the PHLS fears that unless a vaccination programme is introduced, incidence of the disease in the UK could grow to match that in the Third World.

While in the UK less than a half a per cent of the population has the disease, the incidence in India is between five and 10%.

Plea for vaccination

Dr Mary Ramsay, from the PHLS in London, said an effective vaccine existed but was seldom given to injecting drug users.

"We've had very stable figures since the late 1980s, but a sharp increase in the past two years," she said.

"What concerns us most is that this could be the start of a much bigger increase. But it is a preventable disease, and there is something we could do about it."

The Department of Health said part of the �50m being given to health authorities for drug services over the next three years was intended to tackle hepatitis B.

A spokesman said: "We accept that injecting drug users are one of the highest risk categories and for that reason they are a priority."