DEER numbers have returned to levels not seen in Britain since the Norman conquest, a new report has claimed.

So many are roaming the countryside they are fast becoming a menace, a Government study has warned.

Scientists at Natural England say they are munching their way through undergrowth in woodland habitats, threatening rare native species.

Deer were hunted close to extinction in the 18th century, but numbers have bounced back to two million after the introduction of species like muntjac, fallow and Chinese water deer that are smaller and breed faster.

Dr Emma Goldberg, of Natural England, looked at the impact of deer in 80 protected Sites of Special Scientific Interest. She said deer browse out habitat needed by mammals like dormice and insects like butterflies.

A major concern about deer is the spread of cattle disease like bovine tuberculosis and foot-and-mouth.

Currently around 350,000 deer are killed every year, mostly by rifle, but it could be increased to 500,000. Trained hunters carry out the culls and the venison is then sold.