West Hertfordshire health authority chief executive Carolyn Regan has good reason to hope that the National Institute for Clinical Excellence will help managers fend off accusations of rationing.

Her authority's threat to dock the pay of a GP who issued NHS prescriptions for Viagra won unwelcome publicity last week - and a rap over the knuckles from the NHS Executive.

In a letter to Viagra manufacturer Pfizer's legal department, Kevin Guinness, the Executive's head of pharmacy and prescribing, says: 'We have informed the HA that we do not accept its interpretation of the legal position.'

Ms Regan points out that only 'two GPs out of 300' in her area have prescribed Viagra on the NHS. And the sum she threatened to withhold was purely the cost of prescribing and dispensing, around£30. But unrestricted prescribing of the£4.84 pills could cost her HA£500,000 a year, she says.

The HA had asked GPs to pass on details of 'special circumstances' for prescribing Viagra. Ms Regan says this was no different to 'requests for additional funding we get all the time', such as for cholesterol-lowering drugs for patients at risk of heart attack. She hopes national guidelines for controversial treatments 'will mean we can stop re-inventing the wheel', with each HA having to weigh up the scientific evidence. Ms Regan wants NICE to provide consensus and 'an early warning system' for how new treatments should be managed.

Dr Peter Simmons, one of two GPs in the area prescribing Viagra on the NHS, says he will never provide 'clinical information' to the HA 'for reasons of confidentiality'. He, too, points out the row is over small figures - he has written NHS prescriptions for only two patients, a total of nine tablets. But he will not change his stance until Mr Dobson introduces regulations. 'I am obliged by my terms of service to prescribe all drugs required by patients that are available on the NHS, ' he says.