The Lancet says there is insufficient evidence to be sure that the drug is either safe or effective and has warned that the Government's off-the-cuff decision to bypass normal regulatory procedures was flawed.

The journal has entered the fray over patient access to Herceptin after a health authority "revisited" its decision not to provide the drug for a mother of four following the dramatic intervention of Patricia Hewitt, the Health Secretary.

Breast cancer victim Elaine Barber, 41, had intended to take her case to the High Court 41, but her local primary care trust changed its mind and agreed to give her the 21,000 treatment.

The health authority, North Stoke PCT, had previously argued that the drug's efficacy was unproven and, on that basis, it was too expensive to fund its use.

That view is supported in The Lancet which argues that the case for giving Herceptin to women with early HER2-type breast cancer is still not reliably proven, and the journal has condemned the "hype" that forces premature decisions to be made about treatments.

It is also critical of an editorial published in the New England Journal of Medicine last month which described Herceptin as "maybe even a cure".

This article apparently prompted Ms Hewitt to announce that the drug should be made available on the NHS on demand, even though it has not completed approval trials.

According to the Lancet 'the best that can be said about Herceptin ™s efficacy and safety for the treatment of early breast cancer is that the available evidence is insufficient to make reliable judgments'.

The journal says 'it is profoundly misleading to suggest, even rhetorically, that the published data may be indicative of a cure for breast cancer'.

The availability of new treatments in England and Wales is largely determined by the National Institute for Health and Clinical Excellence (NICE), which vets medicines.

NICE recommended Herceptin for women with advanced breast cancer who had the HER2 gene mutation linked to the disease in March 2002.

While the process leading to the decision was criticised as taking too long, NICE has insisted that its primary concern was to provide reliable advice backed up by sufficient evidence.

An even more intense debate blew up earlier in the year concerning the promising early results from a study of women with early breast cancer who were given Herceptin.

The findings from this study, presented at the annual meeting of the American Society of Clinical Oncology, sparked a wave of demands for the drug, and some countries, such as France, bypassed their normal approval procedure to make Herceptin available.

The journal stresses that regulatory agencies and bodies such as NICE play a pivotal role in translating research evidence into clinical guidance, and it is vital that their decisions are made carefully after considering the totality of available evidence; they must be free from political, special interest, or media influence, no matter how well meaning.

North Stoke PCT had previously argued that there was not enough evidence supporting the long-term efficacy of the drug to justify its expense.

In a carefully-worded statement it said that Mike Ridley, the chief executive, has met Ms Barber and agreed to uphold her appeal, but that the introduction of any new expensive treatment inevitably provokes a review of the PCT ™s investment priorities.

They say there is no contingency budget in the present financial year for the prescribing of adjuvant Herceptin.

It is estimated that the additional cost pressures for the City of Stoke on Trent will be 700,000 in the year 2006/7.