Egg thieves, hare hunters, nuisance bikers and fence thieves have forced a wildlife reserve to dig a kilometre-long security ditch.

The RSPB, which owns and manages Shorne Marshes reserve, has spoken out over a number of crimes in the area over the past few years, resulting in the construction of a security ditch across the northern edge of the marshes.

The trench was built “to prevent anti-social and illegal activities taking place on the reserve”, according to planning documents.

Earlier this year, thieves managed to break into the marshland and steal an electric fence worth £5,000, according to the bird charity.

The site has also suffered numerous incidents of egg theft from the sanctuary’s rarer birds, such as black-winged stilts.

There have also been reported incidents of bikers trespassing onto the site and tearing up the boggy land.

Hare coursing has also been a problem on the marshes, according to Rolf Williams, Kent spokesman for the wildlife charity. This illegal sport typically involves the pursuit of hares with dogs.

Mr Williams said: “We have a no-tolerance policy for criminal activity. The police, nine times out of 10, send an officer to come out to catch these people. They have bike teams who can catch those who get on to the reserve.”

Aside from security, the ditch was also constructed to act as a water reservoir, maintaining water levels in drier months, protecting a nearby gas compound from flooding, and increasing wildlife diversity.

Shorne Marshes is an important breeding ground for birds such as redshank and lapwing.

It site is closed to public access due to the nature of the terrain and the fact it is located close to the Metropolitan Police’s practice firing range.

But it can be viewed from the Saxon Shore Way footpath or the Sustrans cycle path.

"We have a no-tolerance policy for criminal activity. The police, nine times out of 10, send an officer to come out to catch these people" - Rolf Williams

Police Sergeant Carli Deacon of the Gravesham community safety unit said: “We are committed to tackling rural crime and our officers regularly patrol the Shorne Marshes area.

"A new Kent Police Rural Task Force is being launched later this year, to prevent and detect crime in our rural communities.

“Dedicated officers will work together as a coordinated unit, targeting those who commit crime and listening to the concerns of people living in rural Kent.

“I would appeal to the public to report all crimes to us on 101 or 999 if it an emergency, crime is in in progress or life is in danger.”