There may not be one solution which fits across the country

Professor Peter Ormerod, BTS

By 1998, the number had risen to 112.

London saw most of the increase and in both years, most of the patients were male and black African (acquiring HIV through heterosexual encounters) or white (through sex with men).

But as HIV infection may be undiagnosed in TB patients, and TB may be unreported in HIV patients, the researchers suggest the true figure is likely to be higher.

The researchers estimate HIV contributed to 8.5% of the increase in TB cases between 1993 and 1998.

London concerns

People may carry the TB infection for many years but only develop the disease when they develop HIV which suppresses their immune system.

This means TB symptoms in HIV patients are generally spotted and identified.

But HIV infections in TB patients may be less apparent when they are diagnosed.

Writing in Thorax, the journal of the British Thoracic Society (BTS), the researchers said doctors in London should be particularly aware of the risk that patients with either TB or HIV may also have the other condition.

Dr John Watson, head of the respiratory division at the PHLS and one of the report's authors, told BBC News Online the findings "could be an argument in favour of offering testing to all patients with TB under the age of 55".

He said current guidelines which say TB patients should only be offered testing - along with counselling and informed consent - if they are from high-risk groups or areas should be reviewed.

Lisa Power, head of policy and campaigns for the Terrence Higgins Trust, said: "We support the offering of an HIV test to anyone who may have been at significant risk of contracting HIV, but we do not support compulsory testing under any circumstances.

"Doing so is counterproductive, and can cause people to remove themselves from medical services."

'No one solution'

But Professor Peter Ormerod, former chairman of the BTS, told BBC News Online that even in 1998, only a small proportion of people had both TB and HIV.

And he said while London had a high number of cases, other areas had very few.

He said in his hospital, in Blackburn, Lancashire, two people with both HIV and TB had been seen in 20 years.

"There may not be one solution which fits across the country.

"What's relevant, or appropriate for Greater London may not be appropriate for most parts of the country."

But he said the committee would consider the information from the study.