Correspondent, Fergus Walsh: "Experts say current treatment is much improved."

The inquiry at St George's Hospital revealed that at least one woman died of cervical cancer after being given the all clear by the service.

All the women had already had moderate or severe abnormalities detected by a standard smear test.

BBC Health Correspondent Richard Hannaford reports

The possible errors occurred at the next stage when they underwent a more detailed cervical examination in the hospital's colposcopy clinic, carried out by Mr Graham Barker.

Independent appraisal

Two independent experts were asked by St George's to review the cases of 19 of Mr Barker's patients, seen between 1989 and 1996. All had developed cancers.

The experts found that his treatment of eight cases had been sub standard, and in four there was cause for concern.

4.5 million smears are examined by pathology laboratories each year

They also regarded a method used by Mr Barker to remove pre-cancerous cells as unreliable.

His judgement was called into question after another consultant at the hospital began seeing women who had been given the all clear by the clinic and had subsequently gone on to develop cancer.

Hospital concern

The hospital stresses that no method of detecting cancer is 100% accurate.

Andrew Dillon, chief executive of the hospital, warned that other hospitals in the NHS needed help to review their services. Mr Dillon expressed his regret about the anxiety the recall will cause women, but was confident the hospital was doing the right thing.

Dr Andrew Dillon: Regret and sympathy

He said: "We very much regret that this is having to happen, but we think it is the right thing to do to make absolutely certain the care that women receive is appropriate."

Mr Barker has agreed to withdraw from all clinical activity at the Trust until the recall is completed.

A spokesman for the Department of Health said: "We are certainly aware of the situation and are glad that [the Trust is] acting speedily to allay women's concerns."

Recent screening scares

St George's is the latest centre to be investigated for faulty screening.

BBC Health Correspondent Fergus Walsh with a colposcope used to look at the cervix

At the Kent and Canterbury Hospital, 90,000 smears were rechecked two years ago after five women developed serious cancers. A further 300 required urgent treatment.

An inquiry found widespread flaws in the screening operation.

Despite these worries, the screening programme has had great success in helping to reduce the number of deaths from cervical cancer - down about 40% on 1979.

St George's Hospital has issued a freephone number for women who may be concerned about their health: 0800 3286905.

In a separate development in South Wales, it has been revealed that 14 women developed cancer after they were wrongly told that their cervical smear tests were normal four years ago.