With their formidable six-feet wingspan and hefty undercarriage, a swan looks as reliably airborne as anything else around Heathrow. But every autumn and winter on the M25, crash-landing juvenile swans cause as much traffic congestion as car accidents. The worst black spot is junction 13, where the motorway crosses the Thames, and where the Highways Agency are called out so frequently that they have had to undertake training in the art of swan removal. And it is a pattern that is being repeated all over the country as swan?related road injuries increase.

Fortunately, most of these road injuries are not life-threatening and the lucky ones will end up at the national swan sanctuary in Shepperton where they are examined, treated and rehabilitated before being finally released back into the wild.

Founded in the early Eighties by Dorothy Beeson in her back garden, when she came to the aid of a male swan with fishing line stuck in its bill, the sanctuary now treats more than 3,000 swans a year on the new five- acre site in Shepperton. The size and scale of the operation has surprised Beeson, who has been awarded the British Empire Medal for her work with swans. “I never set out to run the largest swan hospital in the country; I actually prefer cats. But back in the Eighties, swan numbers were reaching critically low numbers due to lead poisoning and I knew I had to do something.”

The new sanctuary has been developed on the site of an old gravel pit and consists of a hospital wing complete with operating theatre, a heated intensive care section and a recovery area with an exercise pond. A long corridor lined with boxes of lettuces leads to the operating theatre where a swan has just been operated on to repair a wound. It was picked up by the RSPCA that morning from a park in Southall and brought to the hospital. Now safely installed in the intensive care area, it looks remarkably well and should make a full recovery. “We expect to return 86 per cent of our patients to the wild,” explains Beeson. “Euthanasia is rarely used and only the really disabled birds stay permanently.”

Outside the hospital building, in a small wooded area dotted with ponds and aviaries, is a noisy community of web-footed wonders. For as well as swans, Beeson takes on a wide variety of other rejected and injured species, including storks, herons, geese, gulls, grebes and even a few owls and parrots. Beyond this is a large five-acre lake that connects to the Thames. It is packed with swans, waddling on the banks or gliding serenely on the water like huge meringues.

So why are swans so accident-prone? “The majority of the injuries we see are to do with human activities,” says Beeson. “Fishing line and hooks left behind by anglers, out-of-control dogs and then there are the roads. Swans are not the best flyers. If they miss a wing beat they can easily plummet.” Some people think that swans mistake roads for rivers but it’s apparently more to do with the turbulence caused by the heavy traffic, which can literally suck birds out of the sky. Once landed they need a long run before they can take off again.

Wing amputations from road accidents and air-rifle injuries are all in a day’s work for Beeson who, together with a skilled vet and an anaesthetist nurse, witness triumphs and tragedies in equal measure.

She still remembers a horrific incident when some young swans were lured by bread, only to be doused with petrol and set on fire. “Swans mate for life and so if one is injured we will always bring the partner, and sometimes the whole family. I’ve seen a male [cob] rear an entire brood when his mate died. It was very moving.” Once the birds recover they will be returned to where they were found and, if they can’t protect their territory, they may be sent to a private protected water.

Next spring sees the opening of a new visitor centre. It will be the first time that the general public will be able to see the sanctuary and will bring in much-needed funds. “It costs £150,000 a year to run this place and up until now we have had to rely on the generosity of corporate sponsors.” It will also be a chance to educate people about the dangers that face swans everyday. “Swans are very spiritual creatures,” says Beeson. “They can communicate their feelings and, at the end of a busy day, nothing cheers me up more than disappearing down the lake with a few loaves.”