Lives are being put at risk because ambulances are not getting to critically ill or injured patients on time.

Figures published by South East Coast Ambulance Service reveal a postcode lottery for ambulance response times across Sussex.

A paramedic or ambulance technician is supposed to reach 75% of patients suffering life-threatening emergencies such as heart attacks or strokes within eight minutes of a 999 call being made.

However patients in some parts of the county are getting a significantly better response than those in others.

Ambulance bosses say overall response times have improved over the last 12 months but agree there is still work to do in some areas.

Over the year, an average of 83.5% of patients in Brighton and Hove were reached on time, compared to 75.9% in West Sussex and 76.8% in Hastings and Rother.

However only 70.9% of those in the East Sussex Downs and Weald area were seen within the eight minutes demanded.

The results show patients in more rural parts of the county are more likely to experience delays than those in towns and cities.

Tony Reynolds, chairman of the Central Sussex Independent Patients Forum, spoke of his concerns about the figures.

He said: “Lives are being put at risk. When calls are as urgent as these it is vital that people are seen as quickly as possible.

“The idea that people in some areas are having to wait longer than they should is disturbing.

“The figures may be improving overall but there are still places where people are having to wait too long and the ambulance service needs to focus on them.”

The bad weather that hit the county in December and January added to the pressures facing ambulance crews, even in urban areas.

On December 20, when Brighton and Hove, struggling to cope with heavy snow and treacherous roads, a critically ill patient, waited just over an hour and a half for an ambulance to arrive.

The service, which covers Sussex, Surrey and Kent, says it was the second highest performing ambulance trust nationally for Category A calls, reaching 76.3% of life-threatening emergencies within eight minutes in 2009/10.

A spokeswoman said: “The improved trust-wide performance was in spite of the severe weather earlier this year and is credit to the commitment and effort of our staff and members of the public who supported us during a very challenging time.

“The trust recognises that as performance is broken down to smaller geographical areas, variation occurs.

“We are not complacent and have carried out a number of improvements.

“These include regularly reviewing performance and monitoring shift rotas to ensure maximum emergency cover at all times.”