As paramedics cut away the remains of the wrecked vehicle, a voice-over intones: 'The nearest hospital is 20 minutes away - and she only has 10 minutes to live.' The picture pans across to take in a descending helicopter. 'The air ambulance will have her there in five.'

You may have seen the television advertisement for air ambulances. There are 13 in all, but only in Scotland and London do they get NHS cash. The purpose of the advert is to get you to donate to the National Association of Air Ambulance Services.

I had expected the NAAAS website to be dominated by action shots of helicopters in action, but found it surprisingly muted. What you do get is quite a lot of information about the 12,000 or so missions air ambulances undertake each year and how they are crewed.

National data gives you the big picture, but follow through the links in the section titled 'And now. . .'to the local services - Devon Air Ambulance Trust is a good example - and you will find a more human picture of the work.

On 15 April, the desperate parents of a three-year-old stopped their car to dial 999 as their daughter choked on a coin. But they were unable to pinpoint their location, and Devon's helicopter had to race the length of the motorway before spotting them and whisking the child to hospital.

A few weeks earlier, a paraglider had plunged 160 feet onto Exmoor, breaking his leg. The spot was so isolated that road vehicles could get nowhere near, and the man had to be stretchered across rough terrain to a waiting helicopter.

Moving on, the most professional site is London's Helicopter Emergency Medical Service - lots of action pictures, standard operating procedures and research for the professional - even a print-it-off, cut-it-out and glue-it-together HEMS helicopter to keep on your desk.