A Midland ambulance service which may be axed under plans to create a single regional body has revealed how patient care could be compromised.
The four trusts which serve the region are Coventry and Warwickshire, Hereford and Worcester, Staffordshire, and West Midlands Ambulance Service which covers Birmingham, Solihull and the Black Country.
In June, the Department of Health revealed plans to halve the number of trusts in England from 32 to 16 by next April.
But bosses at Staffordshire Ambulance Service fear their recorded high standards of performance will be brought down by merging the four trusts into one.
Since 1994, the trust has pioneered the use of System Status Management (SSM) to improve their standards of pre-hospital care.
Figures published on the trust's website reveal it is the cheapest in the region. Under the new Payment By Results scheme trusts are given scores between zero and 140, the optimum score being 100.
Staffordshire Ambulance Service has a ranking of 72 - the second lowest within the NHS.
Coventry and Warwickshire scored 93, the West Midlands' figure is 96, but Hereford and Worcester score is 125, one of the highest in England.
The statistics also show that Staffordshire attends more emergency calls than any other Midland ambulance service.
Nearly nine out of ten calls (88 per cent) received by the trust's control staff are classed as Category A - 13 per cent more than Hereford and Worcester - and paramedics attend each of those calls within eight minutes.
Nationally, 75 per cent of all calls to ambulance services are classified as Category A, and on average 96 per cent of those are attended.
Responses to 999 calls involving heart attacks show an even wider gap between the four Midland ambulance services, with two performing below the national average.
West Midlands attempt to resuscitate 536 people per million, from a cardiac arrest but only succeed in reviving 48 patients per million.
Paramedics in Hereford and Worcester attended to 573 people per million, and saved 56 patients per million.
In comparison ambulance crews in Staffordshire attempted to resuscitate 931 people per million, and revived 256 patients - almost four times the national average of 67.
The ability to administer "clot-busting" drugs can also save lives en-route to hospital, but levels of thrombolysis vary radically across the region.
West Midlands gave just ten patients thrombolytics, followed by Coventry and Warwickshire where 45 people benefited from this treatment.
In Staffordshire, paramedics gave this life-saving treatment to 303 patients - nearly nine times the national average of 35.
Roger Thayne, chief executive of Staffordshire Ambulance Service, said: "We're in a 'life and death' service and wherever we get it wrong, we have to address those issues very quickly.
"If we're going to have an regional ambulance service we should have one with these standards. There's no prospect of our standards going down as a result."