Five hundred hospital consultants say raising taxes has failed to deliver the necessary standards of healthcare. In a full-page advert in the Times, the group Doctors For Reform has called for compulsory health insurance.

Consultant Dr Maurice Slevin said: "The time has come for a genuine debate on the future of healthcare."

The group says the NHS will not be able to meet public expectations. But the Labour Party has claimed the group is a Conservative Party "front". The move comes as ex-bank chief Derek Wanless publishes his second report on improving the nation's health. 'Profound mistake'

The medics are challenging ministers who ruled the NHS should be funded by taxation, following an inquiry by Mr Wanless two years ago. In its launch pamphlet, Doctors for Reform says: "We aim to start and participate in a proper and informed national debate on the choices ahead of us.

"The issues are beyond party politics and we believe... we will make a profound mistake if we leave this debate to politicians." The group points to other systems, such as in France, Germany and Switzerland, which have a diverse range of healthcare suppliers and mixed funding systems, such as social insurance.

The doctors claim the NHS, in its current form, can no longer be considered the finest healthcare system in the world. Poorer people would have their insurance premiums subsidised or paid virtually in full, says the paper. Dr Maurice Slevin, a consultant medical oncologist, said the NHS is unable to treat the patient as a consumer.

"I have patients who say they feel they are victims of the system," he told BBC News Online. "This is not a drive to privatise but a drive to give people consumer power and stop them being treated in this very inefficient manner."

A founding member of the group, Christoph Lees, a consultant in obstetrics and foetal maternal medicine, said: "We owe it to ourselves and future generations to have this debate now." Government rejects idea

The doctors' call was rejected by Health Secretary John Reid, who said the current system was fairer. Speaking on BBC Radio 4's The World At One, Dr Reid said the French system was effectively bankrupt with a 10 billion euro deficit. He said: "What is being suggested here is a system which is not funded by everyone, it is a social insurance system ... where it is only funded by employers and employees - those in work."

Dr Reid said that was effectively a tax on work and was inequitable as it would give contributors a far bigger say over their treatment. Doctors for Reform were not in tune with thinking across the NHS, he said. Tim Yeo, Shadow Secretary of State for Health and Education, Tim Yeo MP, said the government's response was "outrageous". He said: "I find it hugely depressing that the government will not tolerate any other opinion on the NHS other than their own." The group insists it is an all-party group that did not back the Tory "patients passports" voucher policy. The names of the hospitals where the doctors work is not included in the advert.