The first new TB vaccine for 80 years is being tested in clinical trials in South Africa.Oxford University researchers say that the jab, given alongside the current BCG vaccine, could protect people better from the disease.

TB kills more than two million people worldwide a year, and drug resistant forms are becoming more common. Charity TB Alert said an effective, cheap and long-lasting vaccine could justify widespread use in the UK.

The Health Protection Agency recorded more than 8,500 cases in 2005, but the BCG vaccine, which used to be given to all schoolchildren in the UK, is currently targeted only at communities with high rates of the infection, such as immigrant groups and the homeless.

The new vaccine has already passed safety trials in the Gambia, and the latest tests in the Western Cape area of South Africa, where one in 100 infants has the illness, will reveal if the extra jab works better than BCG alone.

Dr Helen McShane, the Oxford University and Wellcome Trust researcher leading the project, said: "This vaccine is safe, and stimulates very high levels of the type of immune response we think we need to protect against TB.

"It is important for us to test whether or not this vaccine does work to stop people getting TB."

'One step ahead' The results of the Gambian trials suggest that the vaccine is having a big impact on how the body's immune system is primed to resist TB infection.

It works by stimulating immune system cells called T-cells to produce a stronger response to the BCG jab. TB Alert, a charity which campaigns for wider awareness of the global cost of TB, said that a new tool in the fight against the disease would be a "great step forward".

A spokesman said: "The TB bacterium has for too long managed to stay a step ahead of human efforts, as shown by the appearance, especially in HIV positive populations in southern Africa, of a strain of tuberculosis resistant to virtually all known drugs."

She added that if the vaccine proved to be safe, cheap and far more effective than BCG, with its effects lasting throughout life, then the reintroduction of universal immunisation in the UK "might be worthwhile".