Health officials have rejected claims that government targets are leading to life-threatening 999 delays.

GPs had warned in a report out on Friday that seriously-ill patients are being kept waiting because ambulances are being diverted to minor calls in order to meet a key government target for response times.

Ambulances must respond to calls within eight minutes in at least 75 per cent of cases for each local trust.

Doctors have told BMA News that, in order to meet the demand, non-emergency calls are taking precedence.

BMA GP negotiator Peter Holden said: "The drive to achieve response times is overriding clinical priority. It requires a political decision to allow ambulance services to bypass inappropriate 999 calls."

But a Department of Health spokesman rejected the claims and argued that by next year the government will have invested £32 million in more staff, vehicles and new equipment.

"Irrespective of who makes the 999 call, the ambulance service despatches an ambulance to all patients in a life-threatening situation who require emergency treatment," he said.

"We have received no evidence to the contrary. All ambulance trusts are expected to respond to 75 per cent of immediately life-threatening calls - category A calls - within eight minutes."

The department's response was dismissed by Dr Evan Harris, the Liberal Democrat's health spokesman, who claimed "crudely imposed" national targets were distorting clinical priorities and putting lives at risk.

"Ambulance services in parts of the country are free to place emergency calls in differing categories of urgency. This can simply be a way of meeting response time targets for the most urgent calls, but also endangering the safety of those 'lower priority' patients," he said.

"This is not acceptable, it is not ethical and the government must drop its target obsessed health care regime and remember that patient care not political need comes first."