AIR ambulance crews have been drafted in to airlift casualties to hospital after heavy snow made driving conditions difficult for road-bound ambulances.

The North West Air Ambulance, based in Blackpool, recorded one of its busiest weekends since it started three years ago, after being called out to five missions on Saturday and six on Sunday , compared with the usual average of three or four a day.

Liam Donnelly, a paramedic and one of the flight crew, said: "Even a minor injury starts to become potentially life-threatening as time goes on, especially if you are caught out on a fellside.

"A broken ankle when you are in freezing temperatures can start to become serious in such conditions.

"In previous years, before the air ambulance service was set up, it would have taken hours to get to some of these casualties, whereas to get to the scene, deal with the casualty and get them to hospital, has been taking us around 40 minutes."

Crews had also been called to several scenes where they airlifted a casualty to the road-bound ambulance, saving them time, Mr Donnelly said.

In one case on Sunday, in Edenfield in the Rossendale Valley, a man had to be airlifted to the ambulance by the air crew after injuring his back sledging on a hillside.

In another on Saturday, the air ambulance was called to a remote farm in the Trough of Bowland, which was almost impassable by road, where a man had collapsed.

The crew assessed and treated the patient and then with the assistance of the land crew transferred him from the house to the helicopter, before taking him to the Royal Lancaster Hospital, with a flying time of just five minutes.

On Sunday morning the helicopter went to two accidents on the M61 near Chorley. The first involved five vehicles and the second a car which had rolled over and come to rest on its roof on the embankment.

The crew also flew to an incident in Rivington where a driver managed to crawl out of an overturned vehicle.

The air ambulance, which is financed by charity donations, has seen its numbers of missions increase steadily since it was set up. It has flown 2,043 missions in three years, and in the first six months of this year, had already flown more missions than the whole of its first year -- 605.

Mr Donnelly said: "We arecalled out more because the various authorities are more aware of our presence and know they can call on us. Our time factor is much better, especially at this time of year. Flying time from the scene to hospital has been between six and 10 minutes."