However, the NOP survey found that women are still more likely to have a smear test now than two years ago, and most realise the tests can save lives.

Two-thirds of women questioned were aware of recent publicity about failures in the system.

These include test errors at Kent and Canterbury Hospital which resulted in eight women dying and 30 others needing hysterectomies.

Three women, Sandra Penney, Lesley Cannon and Helen Palmer are waiting to hear how much compensation they will receive after the High Court ruled two weeks ago that the hospital was negligent in not detecting abnormalities.

Other scandals involving women across the country are still being investigated.

Of women over 20 who were aware of the negative publicity, 49% were "less confident" in the service than they had been previously.

But despite the failures, 23% of women said they were more likely to have a smear now than two years ago.

Only 12% said they were less likely to agree to a test and only one in 20 GPs reported a fall in the number of women attending for smear tests.

Of the women who had heard of the recent scandals, seven out of 10 still professed themselves "happy" with the quality of the service.

The survey found that just 17% of GPs said they had less confidence in the system following the recent cases.

Nine out of 10 doctors said they were happy with the quality of the cervical screening system.

Up to 800 lives are saved and 3,900 cases of cervical cancer are prevented every year by screening.

Onus on GPs

The smear system broke down at Kent and Canterbury Hospital

Marianne Purdie, director of NOP Healthcare, said: "Patients have clearly lost a degree of confidence in the cervical screening programme as a result of the recent highly-publicised failures.

"Although this does not appear to have deterred the majority from continuing with the programme, with such an obvious discrepancy existing between the views of GPs and those of their patients, perhaps the onus should be placed on GPs to transmit the faith that they have in the system to their patients."

A spokeswoman for the National Screening Programme said: "While we are concerned that half of the women surveyed are less confident than they were before, it is important not to lose sight of the fact that the vast majority of cervical screening is problem free.

"The programme is suffering because of a few, regrettable problems which have created publicity out of proportion with the high standards of screening being delivered to the majority of women."

Dr Simon Fradd, chairman of the Doctor Patient Partnership, established by the British Medical Association and the Department of Health to help patients make best use of the NHS, said it was important that GPs stressed how beneficial smear tests could be.

Dr Fradd said: "Any health professional has a responsibility to get over the positive message that if you screen women aged 20 to 64 every three years we will prevent 91% of cervical cancers."

Following the Kent and Canterbury cases responsibility for testing was taken out of the hands of hospitals who were competing with each other for the right to screen slides.

Instead local health authorities were made directly responsible for screening in their area.

The Government last year introduced new targets for local health authorities to improve the screening programme and ensure as many women as possible participated.