Every year, 660,000 women aged 25-29 are invited for screening in England. But in 2005-06, only 69.4 per cent of them did so, compared with almost 80 per cent in 1995. The drop has been attributed to complacency and an increasing reluctance to undergo an unpleasant and invasive procedure.

A similar trend has been seen in women aged 30-34, whose attendance is down by about 800 a week.

The risk of abnormal findings in smear tests is highest in the 25-29 age group. From the figures of those who did attend it is possible to estimate that about 2,000 women with abnormal findings — the immediate precursors to cervical cancer — are going undetected each year. They are at high risk of getting the disease if they continue to avoid screening.

Alison Fiander, gynaecological oncologist at Wales College of Medicine, University of Cardiff, said: “It is worrying that the very women most at risk of precancerous cervical disease — younger women — are those who are choosing to stay away from screening in increasing numbers.”

Anne Szarewski, clinical consultant for Cancer Research UK and a researcher into human papilloma virus, the cause of cervical cancer, called on young women to attend clinics. “It’s a big worry if young women start to miss their smears. The peak age for cervical cancer to strike is while women are in their late thirties, but it can occur earlier.”

Young women contacted by The Times yesterday described how even thinking about the test made them shudder and led to months of procrastination.

Simone, an administration worker, said: “A smear test can be so uncomfortable and it’s pretty invasive — it’s certainly not a nice thing to have done. I just keep putting it off.”

She added that she was not concerned about the threat of cervical cancer. “Of all the health things that can go wrong, that’s not really one I think about, though I know I should just bite the bullet and get it over with. But I’m very busy with work and it’s hard enough to go the doctor when you’re actually sick, let alone for a preventative measure.”

A recent study of trends in cervical cancer in 13 European countries found it was holding steady or falling in countries that had screening, such as Britain, but was increasing in those without, such as Spain and Slovakia.

To date the cervical screening programme has been highly successful. There are about 1,000 deaths a year from the disease in England, but it has been suggested that this figure would be as high as 6,000 without the programme.

Julietta Patnick, director of the NHS Cancer Screening Programmes, said that the falling attendance figures were being investigated. Preliminary research suggested that they had been caused by increasing fear of the discomfort and embarrassment of the procedure.

“Of course we are keen to understand why women today may be more embarrassed than perhaps ten or twenty years ago,” Ms Patnick said recently.

“Another key issue could in fact be the effectiveness of the screening programme. A reduction in rates of cervical cancer means it is now a far less common disease, so people don’t tend to worry about it so much. Most people may not know anyone who has had the disease.”

Attendances in Wales across all ages have also fallen from a peak of 85.8 per cent in 1992-93 to 75.4 per cent in 2005-06. As in England, women aged 25-29 had the lowest attendance rate.