The air ambulance celebrates 25 years of live-saving service today.

The vital aircraft, funded almost entirely through donations, has responded to an incredible 25,000 call outs over the last quarter of a century.

It often makes the difference between life and death for thousands of seriously injured people.

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Founder and former chief executive Kate Chivers said: "Over the years, owing to the skill and professionalism of its crews, the dedication of its volunteers, the vital support of the press, radio and TV, and the extraordinary generosity of individuals, organisations and businesses throughout the community, it became possible to maintain and develop this unique charity into the exceptional lifesaving service which has been an inspiration to others."

The Kent air ambulance flew its first mission at Christmas 1989.

The service's first ever patient was 16-year-old Michelle Leather, who lived near Tenterden, and was flown to the William Harvey Hospital, Ashford.

Video: Kent Air Ambulance reaches 25th anniversary - Graham Stothard reports

Thanks to the helicopter, Michelle was receiving treatment within seven minutes of being released by the South East Thames Air Ambulance team, as they were known then.

Since that first mission, the air ambulance has seen the introduction of doctors on board, and expanded the service with a second helicopter.

It's also become the fist service of its kind to carry blood on board to enable transfusions at the scene, and most recently, has started responding to emergencies at night.

Tonight invited guests including supporters, volunteers, former patients, crew, staff, trustees and local dignitaries will gather at Canterbury Cathedral for a special service to mark the anniversary.