Health Secretary Frank Dobson talks to BBC Radio

Instead, he has ordered trials of the impact of the drug on patients at high risk of flu complications, such as the elderly and those with asthma.

Mr Dobson says the Department of Health will re-consider his decision in the light of those results in time for winter 2000/01.

Dr Trevor Jones, spokesman for pharmaceutical companies and Stephen Thornton Chief Executive of NHS Confederation

Mr Dobson's ruling follows a recommendation that the drug should not be freely available on the NHS by the new National Institute for Clinical Excellence (NICE).

NICE is a committee of medical experts set up by the government to rule on which drugs should be used by the NHS. Relenza is the first drug it considered.

The BBC's Niall Dickson:"This is not the end of the story for relenza"

Glaxo Wellcome, which makes Relenza, strongly urged the government to put its flu treatment on the NHS drugs list, as that would increase its chances of success in major overseas markets.

But the £24 oral spray has been seen as too expensive for the financially-strained NHS and its all-round effectiveness has been questioned.

The institute warned that the drug could cost the NHS £115m if there was a flu epidemic.

However, Glaxo Wellcome says the cost to the UK's taxpayers in a normal year would be £10-15m.

Mr Dobson said that Glaxo Wellcome had acknowledged in its own literature that there was not yet a great deal of evidence of the impact of Relenza on patients at high risk, and that research was still taking place.

He said: "I have asked NICE and Professor Sir John Pattison, the NHS Director of Research and Development, to work with the company to assist with these trials or any other which may be necessary to provide better evidence for NICE to carry out a further, full appraisal before the winter of 2000/01.

"I believe that this decision is in the long term interests of patients, the NHS and research-based pharmaceutical companies."

Put-out threat

Glaxo Wellcome, along with rivals AstraZeneca and SmithKline Beecham, have asked for an urgent meeting with Prime Minister Tony Blair on the Relenza issue.

Earlier this month Glaxo Wellcome chairman Sir Richard Sykes warned that leading drugs companies will consider pulling out of the UK if the government adopts an "antagonistic" attitude towards the pharmaceutical industry. The company has already scrapped 1,700 UK jobs.

Sir Richard told the BBC: "Certainly the British drugs industry is one of the finest examples of a technological industry that has made it in global terms and to create an environment that does not encourage those sorts of industries I find rather disappointing."

Sir Richard dismissed criticisms that Relenza had not been tested on sufficient numbers of people with complications.

He said it was very difficult to get large numbers of such people into clinical trials, and that the drug had been tested on 6,000 people world-wide.

"There is absolutely no question about the efficacy of Relenza. Of course we don't have statistically significant data to show that this drug works in specific groups - that never happens with drugs, drugs are tested in big populations."

'Drug is vital for patients'

Dr John Chisholm wants the drug blacklisted

Trevor Jones, head of the Association of British Pharmaceutical Industry, said patients who needed modern medicines should have access to them.

He said: "This drug has been approved as effective in many countries of the world, it is being used in all age groups suffering from influenza and I cannot see why patients are being denied medicines that are vital to their lives."

But Dr John Chisholm, chairman of the British Medical Association's GP Committee, said Relenza should have been completely blacklisted.

He said patients would still innundate GPs for Relenza prescriptions even though doctors had been told not to prescribe it.