PICTURE the scene. A gentle summer's day, a warm breeze is blowing through the trees, the bees are buzzing and the birds are singing.

It's a beautiful English scene. But it's also a crime scene.

Perched in the trees, the birds look so beautiful, so delicate and fragile.

But when those birds try to fly off they won't be able to. Because some people deliberately smear tree branches with glue so that birds, finches in particular, stick to them.

If a bird doesn't die, the person will come along and pick it off, put it in a cage, pack it off abroad and sell it as a "singing bird".

Which is as illegal as it is cruel.

It's a crime that Cambridgeshire police take very seriously.

In fact, they take it so seriously that our police force is one of only four in the country to have a dedicated Rural Community Action Team (RCAT), of four Pcs, a sergeant and two PCSOs.

"People might think that in an urban place like Peterborough there isn't any crime against wildlife," said Pc Paul Carter. "But they would be shocked. For example, we know that there's an active badger's sett in Hampton, and a bat cave in Stanground. The city centre is full of wildlife."

Pc Carter takes me to Potter's Way, which is a 10-minute car journey from the city centre. As we drive there he is flagged down by a motorist and asked where B&Q is, so it's hardly a secluded little beauty spot.

"We have caught people sticking birds to trees here," he said. "It's called liming. Basically, as with most of our work, members of the public will see something dodgy happening, report it, and we will take it from there."

Why would anyone want to do such a horrible thing? "Money," he replied. "There is an awful lot of money in wildlife crime. Liming, stealing and selling birds' eggs, gambling on hare coursing, trading in animal skins."

Pc Carter is responsible for investigating all crimes against wildlife across the whole of Cambridgeshire. His team is based in Sawtry, and he patrols his patch in a police van.

As he drives, he explains that 10 years ago he was a beat bobby in Werrington, but took a wildlife crime correspondence course with the Department for Environment, Food and Rural Affairs (Defra) and the RSPCA.

He joined RCAT when it was set up three years ago, mainly to deal with hare coursing. There is big money in this sport, with punters watching dogs chasing a hare, and betting on which dog will catch it first.

As well as being cruel to hares, it also mashes up the field it takes place on.

"Some people also like to watch dogs fight," said Pc Carter. "But as that mainly happens in people's homes, with an old carpet put on the floor to soak up the blood, it can be very hard to detect.

"As with most of our work, we are really dependent on tip-offs from members of the public who have seen or heard something odd."

However depressing his job might seem to many of us, Pc Carter loves it.

"I've got the best job in the force," he said. "I've always loved animals, and it's a very worthwhile job, I think. Wildlife crime leads to a lot of other, different crimes.