The London Ambulance Service (LAS) has been rated the best ambulance service in the country.
The Healthcare Commission judged LAS as 'good' for both its use of resources and its services - a better rating than any other service in England.
The commission also said that LAS offered patients good quality of service and that its financial standing was strong.
The Healthcare Commission is the independent watchdog for the NHS.
The annual report said: "Based on our assessment, London Ambulance Service NHS Trust provided a good quality of service to patients, having made significant improvements compared to the previous year.
"It continued to be good at managing its finances."
LAS chief executive Peter Bradley praised the work of the service's 4,000-strong workforce.
"We have had a very challenging few years, but it is a credit to everyone involved that we have done well with our key performance targets and broke even financially," he said.
During 2006/07 the Service handled nearly 1.3m emergency calls, up nearly 5% on the previous 12 months.
It also responded to 2% more potentially serious or life-threatening incidents than in 2005/06.