More ambulances met 999 response-time targets last year, despite a 4 per cent rise in the number of emergency journeys, official figures reveal.
But ambulance services piloting call prioritisation, to ensure life-threatening cases get a quicker response, did not appear to hit response targets any better than those using the old system where all calls were treated equally.
Department of Health statistics show that two of the eight services which piloted prioritisation failed to meet the standard of a response within eight minutes in 50 per cent of emergency calls.
But 22 of the 29 ambulance services which have not prioritised 999 calls achieved the standard.
Ambulance Service Assoc-iation director Roy Saunders said prioritisation had improved performance because the pilots were working to higher standards.
The DoH bulletin says it is difficult to assess the overall impact of change from one year to the next because much depends on local circumstances.
'Nevertheless, over the whole country the proportion of calls with a response within target has been increasing at a time when the workload has been rising at an unprecedented rate,' it says.
Derbyshire Ambulance Service trust, one of two pilots to fail the standard, achieved an eight minute response to life-threatening calls in only 35 per cent of calls.
Chief executive Stuart Ide blamed Derbyshire's poor performance on a 10 per cent reduction in staffing 'due to funding difficulties'. It had previously met national standards.
He said: 'This year our ambulances went out to 4,100 more incidents than they did the previous year, but we have 26 fewer people on the road than before.'
Overall, the ambulance service in England received 3.6 million calls in 1997-98, up 7 per cent. Emergency journeys rose from 2.6 to 2.7 million.
Ambulance Services, England: 1997-98, DoH Statistical Bulletin from PO Box 410, Wetherby