Ambulances are slower to respond to 999 calls than five years ago and the delays may be costing thousands of lives, a study said yesterday.

Ambulances are slower to respond to 999 calls than five years ago and the delays may be costing thousands of lives, a study said yesterday.

Only one ambulance service in Britain is meeting the Government's target for reaching 75 per cent of "immediately life threatening" calls in eight minutes. All 37 services are expected to meet the target by 2001 but most are a long way short and there is huge variation around the country in emergency response times.

The study, in Healthwhich?, published by the Consumers' Association, is based on Department of Health figures. It shows more than 33 per cent of services reached less than 60 per cent of their emergency calls within eight minutes.

The Department of Health blamed a 30 per cent increase in emergency calls and a 52 per cent increase in emergency journeys in the past five years, saying it had invested an extra £21m in ambulance services this year. It disputed the figures quoted by Healthwhich? Four ambulance services had already met the 75 per cent target for life-threatening calls and most were on course to do so by early next year.

Eight minutes is regarded as the outside limit for help to be provided to victims of heart attack. Beyond that ambulance crews are unlikley to be of help. An expert panel appointed by the NHS Executive advised four years ago that the lives of 3,000 heart attack victims could be saved each year if ambulances reached 90 per cent of the most urgent calls within eight minutes.

To improve response times, the Department of Health introduced a system of "callprioritisation" in 1997 under which controllers sort calls to determine which should beanswered first. Immediately life-threatening calls require a response in eight minutes; other emergencies require a response in 14 minutes in urban areas and in 19 minutes in rural areas.

Just over half of all ambulance services have introduced the call prioritisation system and only Staffordshire has exceeded the Government target with 87.4 per cent of the most urgent calls receiving a response within eight minutes. London Ambulance Service was the slowest, responding to 35.8 per cent in eight minutes. Overall 11 out of 16 services without call prioritisation had slower response times in 1999-2000 than they had four years earlier in 1995-96. Among the 21 with call prioritisation, three had worse response times last year compared with 1998-99.

Sue Freeman, managing editor of Which Health? said: "Our analysis of the most up to date figures shows that ambulance services still have a long way to go - what is even more worrying is that response times in some areas are actually deteriorating. We welcome call prioritisation but it must ensure that the most seriously ill patients get treated first.

"Call prioritisation alone will not improve ambulance times. Models like Staffordshire show that a package of measures can achieve successful results."

The research suggests that call prioritisation systems may lead to some life-threatening calls being under-prioritised because the systems used are "not sensitive enough to reliably detect the critically ill".

A simple way of improving response times is to position ambulances close to areas of high demand. Thathas helped Staffordshire imirpove its services considerably.