Women are being forced to wait up to two years longer than they should for breast cancer screening because of financial cutbacks and staff shortages.

Senior figures in the medical profession will warn this week that lives could be at risk because of the delays. Richard Evans, chief executive of the radiographers' professional body, said it was 'scandalous' that the national screening programme was being hampered by a lack of resources. Women aged between 54 and 70 - the riskiest time for developing a tumour - should be called in every three years for a mammogram, which can detect problems at the earliest stage, when chances of survival are highest.

But pressure on the screening system means that in some parts of the country women are having to wait up to five years, according to cancer charities, which means early tumours might go undetected. Evans said that some women, who were recalled after an initial screening had raised concerns, were also having to wait longer.

The Society of Radiographers is calling - alongside the charity Breakthrough Breast Cancer and others - for a significant increase in funding for the service. Evans said shortages of consultant radiologists had been exacerbated because, although radiographers, the technicians who take the images, could be trained to assess them as well, their training programmes were being cut.

'In the current climate of financial constraints, training [for these staff] is one of the first areas being cut, because it is not seen as a high priority,' said Evans. 'That may make very good sense to the director of finance, but for those women waiting to have their screening - or, even worse, who have been called back for a reassessment - that is absolutely not a low priority. The screening programme has demonstrably made a difference to survival rates and it is scandalous that the programme should be held back for any financial reasons.'

The Department of Health wrote over the summer to health authorities reminding them to ensure that women are screened every three years. However, a spokesman for Breakthrough for Breast Cancer said that in many districts that was not happening.

'To get the best out of the programme you need to be screened every three years but, for a variety of reasons, mainly capacity, it often doesn't happen that way. Sometimes the screenings end up every four years or even five years,' he said.

'The fundamental message of the programme is that early detection saves lives. Although lots of women are able to detect lumps in their own body, the programme is able to detect breast cancer before you can actually feel it yourself.'

The national screening programme estimated recently that it was not only saving 1,400 lives a year, but was also preventing unnecessary mastectomies. However, there is concern not only about the programme's workload, but also about its future. The number of women eligible for screening will rise by a fifth between 2005 and 2025 as the post-war baby-boomer generation reaches the danger age for breast cancer, further straining resources.

A Department of Health spokeswoman conceded that there were delays in screening, but said the programme was a 'great success'. Changes - including raising the upper age limit from 65 to 70 and two-view mammograms for greater accuracy - had improved the process, but significantly increased its workload, she said. 'We are aware that this has had an impact on some services in parts of the country maintaining the three-year interval for screening, and we are taking steps to bring all screening intervals back to three years.'

Any 'temporary delay' was due to the improvements, she said. Almost 1.5 million women were screened last year and 12,000 cases of cancer were detected.