When the Christmas lights are switched on in Thornbury this year, Bristol families will have the chance to support the life-saving work of the Great Western Air Ambulance.

Thousands of people are expected to enjoy the launch of the festive season during a night of entertainment in the High Street and it is hoped they will do their bit to help keep the life-saving helicopter service flying.

The Evening Post has joined forces with the Great Western Air Ambulance (GWAA) to help them raise the £1.3 million they need to fund the service through the Sky's The Limit appeal.

And the big-hearted team of volunteers behind the annual effort to light up Thornbury will be encouraging people to throw some coins into the collection buckets to support the new air ambulance service.

They raise money through sponsorship, donations and fundraising events to pay for the decorations, and in the weeks leading up to the switch-on, give up their Sundays to put the illuminations in place.

The air ambulance is not funded by the NHS so the team behind the service has to raise the money needed to attend emergencies.

The crew is made up of specialist paramedics and emergency doctors who fly to the most serious incidents and take the standard of care found in accident and emergency units to the scene.

Paramedics and drugs are paid for by the local ambulance service but doctors work voluntarily and a dedicated charity team raises money for the helicopter, fuel, uniforms and equipment.

Without a minimum of £1.3 million a year, the service would cease.

Members of the air ambulance team should be at the switch-on to meet the crowds and explain what their job entails as well as helping to flick the switch at 7pm on Tuesday, November 18.

George Jackson, spokesman for Thornbury Christmas Lights Association, said High Street will also be closed off for a street fair and funfair, which starts at 5.30pm.

"It's a very good cause and as the service was only formed recently, we wanted to help boost their funds."

All the Christmas lights in the High Street and surrounding roads – except in the St Mary Shopping Centre where the lights are the responsibility of the precinct – are bought, stored, maintained, renewed, put into place and then taken down again by volunteers.

With rising costs and sources of funding becoming increasingly squeezed, the organisation is always looking for more help and hopes to persuade more people to become members of the association.

It usually gets grants from Thornbury Town Council and South Gloucestershire Council and many local businesses also contribute to the cost.

Paul Weir, chief executive of the Great Western Air Ambulance Charity, said: "We are absolutely delighted that the association at Thornbury decided to support Great Western. I'm sure the event will prove very popular and as a result, the charity will benefit."

The air ambulance was called to Keynsham Leisure Centre yesterday just after 11am to deal with a man who had collapsed while on the running machine. The 60-year-old, who had suffered a cardiac arrest, was resuscitated at the scene before being flown to Frenchay Hospital.