Experts have predicted an explosion in the numbers of wild boar roaming the countryside.

Hundreds of the animals are already living in the Sussex Weald following escapes from farms in the Eighties.

Now The Game Conservancy Trust has warned that the creatures could soon multiply into thousands unless something is done.

In Germany, more than 500,000 wild boar are shot every year. An estimated 6,000 of the animals live in the centre of Berlin.

Until about 700 years ago, boar were native to England, along with wolves and beavers.

But boar stopped thriving in the wild at the end of the 13th Century and attempts to reintroduce them during the next 300 years were not successful.

The trust, which is a game and wildlife research charity, says the idea of boar roaming freely again sounds romantic but it could have a serious impact on other species.

Stephen Tapper, the trust's director of policy and public affairs, said: "For several thousand years wild boar were hunted relentlessly by man and wolf and later by man alone.

"If we bring them back we will certainly have to be equally relentless about keeping their numbers down, otherwise we will simply be overrun."

The Department for Environment, Food and Rural Affairs is reviewing how to deal with boar living in the wild.

It is believed they escaped in Sussex when their pens were destroyed in the gales of 1987. The trust said boar may thrive today because they have no natural predators.

It claims they damage crops, spread diseases and, if they are with their young, they can even be a threat to humans.

Dr Tapper said: "We are concerned that Defra does not think the population has grown much over the last decade. They also think that damage is more or less tolerable and losses could be compensated through hunting. But we are not so confident."

In France in the Seventies, 40,000 boar were shot every year. Now the number is 400,000.

The Sussex Wildlife Trust said it was on the fence about what, if anything, should be done to control wild boar.

Conservation director Tony Whitbread said: "The evidence for their numbers is variable.

"As far as I can see the population hasn't grown as fast as all that.

We recognise there may be specific problems, but there can be benefits to wildlife.

"Wild boar roots around in the ground. It has the same effect as when a forester extracts timber. It used to be a native species and it does an ecological job."