The BBC's Emily Cato: "Many patients were affected"

At least 60 patients contracted the virus at the Finchley Alternative Health Centre after receiving an unorthodox therapy called autohaemotherapy in which they were re-injected with their own blood.

Autohaemotherapy involves mixing a small sample of a patient's blood with saline in a syringe and then re-injecting it at acupuncture points on the body.

The Barnet Health Authority, which led the probe, said it was "as certain as we ever can be" that a single bottle of infected saline was the root of the outbreak.

The report found that the clinic had:

• No infection control procedures
• No chemical disinfectants and sterilisation equipment
• Medical records that were heavily bloodstained

Autohaemotherapy involves re-injecting the patient's blood

Hepatitis B, which is fatal in a small proportion of cases, affects the liver and can be transmitted through the bloodstream or via unprotected sex.

Some people recover quickly from the flu-like symptoms but others can carry the virus for years, causing chronic liver damage.

The inquiry team called for regulations to cover skin-piercing treatments to be extended to private practices, and for particular attention to be paid to autohaemotherapy.

It also demanded clearer guidelines for those practising complementary medicine, noting that someone at the Finchley centre with no medical qualifications was able to carry out autohaemotherapy legally.

Little control of complementary medicine

Dr Sukhdev Sharma, Barnet Health Authority's consultant in communicable disease control, chaired the investigation. He said: "Complementary therapies are becoming more and more widespread but there is little control of their practice.

"This outbreak highlights the need for awareness among the public and professionals of the dangers of blood-borne viral illness during skin-piercing techniques.

"There is a need for tighter regulation if we are to stop this happening in the future."

The investigation found that, although a qualified doctor worked at the clinic, his daughter, who had no appropriate qualification, was heavily involved in administering the therapy.

More than 400 people who undertook autohaemotherapy at the Finchley centre between January 1997 and February 1998 were traced and tested.

The qualified doctor involved has been suspended by the General Medical Council pending an investigation.

Michael Endercott, of the Institute for Complementary Medicine, said autohaemotherapy was not a widely recognised form of complementary medicine.

But he said: "There is certainly a need for regulation, and that we would warmly support.

"Most people realise that practitioners of complementary medicine are usually members of a bona-fide register and they should check up the letters after the practitioner's name.