A "fast-track" system is actually pushing some women with cancer to the back of the queue.

At least one in four women diagnosed with breast cancer has not been seen urgently, says a study published today in the British Medical Journal Online First.

The Government set a target in 1999 that a woman with suspected breast cancer should have to wait no longer than two weeks on the NHS to see a consultant after being given an urgent referral by her GP.

But this has created a two-tier system, said Dr Shelley Potter, a clinical fellow at Bristol Royal Infirmary, because if a woman does not get an urgent referral she has to wait on the routine list to see a consultant.

And there has been an "alarming" rise in cancers diagnosed from "routine" referrals.

Most women being referred as urgent cases do not have cancer.

In addition, the waiting times for routine referrals have lengthened due to "the dramatically increased number of patients referred under the twoweek rule, over 90 per cent of whom have benign disease", Dr Potter added.

She said GPs were not to blame because they could not be expected to make a specialist diagnosis in advance of proper testing.

They were bound to play safe by sending many women with breast lumps to hospital for urgent attention.

"Also there's more awareness among women now about breast cancer and some will put more pressure on their GP to be referred urgently," she added.

The study - by staff at the Frenchay Breast Care Centre, Bristol - looked at 25,000 referrals between 1999 and 2005, with GPs classifying each patient as "urgent" or "routine".

The number of routine referrals fell by 24 per cent but two-week referrals increased by 42 per cent. The total number of cancers remained constant. But the proportion of urgent patients actually diagnosed with cancer "significantly decreased" from 12.8 to 7.7 per cent.

The number of routine referrals fell, but cancer cases in that group more than doubled to 5.3 per cent in 2005.

In 2005, around one in four of patients ultimately diagnosed with cancer was referred non-urgently.

Waiting times for routine referrals have gone up to 30 days.

Dr Potter said: "Problems with the system have got worse. We have a two-tier system which is unfair. We need a two-week wait for all women.

"It can be done with a little more resource and some reorganisation. At Frenchay we're training nurses to carry out the gold standard triple assessment - that means putting on just one extra clinic a week."

A spokesman for the Department of Health said: "In 2005, the Government made a manifesto commitment to go further on cancer waits and we are considering proposals to do this as part of the Cancer Reform Strategy to be published at the end of this year."