Some GPs may be stigmatised as 'problem prescribers', but one presentation at the conference showed how following national guidelines by prescribing treatments which have accepted benefits for patients can threaten drugs budgets.

Dr Philip Evans, lecturer in general practice at Exeter University, explained how his four-doctor practice had increased prescribing of statins over the last five years.

Statins are lipid-lowering drugs which can reduce the risk of heart attacks and strokes. There is general agreement they should be used more in general practice and the national service framework on coronary heart disease advocates this. As Dr Evans' practice increased its statins prescribing, the cost rocketed from around£200 a month to£4,000 a month - approximately 10 per cent of its total drugs budget. 'For practices who are actually implementing the evidence it is becoming expensive, 'said Dr Evans. 'The concept of putting large numbers of patients with moderately raised cholesterol on to statins is going to strain the NHS's resources dramatically.'

Royal College of GPs president Professor Sir Denis Pereira Gray said there was a question mark over whether rising prescribing costs could be afforded. 'That tension between good evidence-based medicine and what the system can afford is becoming more evident in primary care, ' he said.