The Liberal Democrats' promise to adopt a 'more trenchant oppositionist approach' to the government was delivered in an attack on the National Institute for Clinical Excellence by the party's former health spokesman, Dr Evan Harris.

Dr Harris, now the spokesman for higher education and women, led a typically densely argued debate in which he claimed NICE had become a means for the government to hide rationing decisions. He supported NICE's initial aim to examine the clinical and cost-effectiveness of drugs and treatments, but was disillusioned by the subsequent decision to force it to take into account 'available resources' in its deliberations.

'There is no way I understand clinical effectiveness to relate to issues - important issues - of affordability.

'They are two different things, ' he said.

Dr Harris, who admitted he has a fellowship with drugs giant Glaxo Wellcome and had study trips to the US paid by Rhone-Poulenc Rorer, attacked the NICE decision to restrict the Glaxo-produced anti-flu drug Relenza.

The NHS should be prepared to buy such a drug, even if there was no evidence that it saved lives, because it would probably be cost-effective in terms of reclaiming working days lost to flu, he said.

'NICE seemed to be saying that on the basis of affordability it and the NHS would not be interested in flu as a disease until there was a drug that is proved to save lives among the elderly.'

Replying, health minister John Denham said the institute would tackle unacceptable variations in the quality of care and treatment and would not override 'decisions made by clinicians and their patients in the consulting room'.