Heritage lovers have hit out after an illegal biking trail was created through an ancient monument at Mousehold Heath in Norwich.

The trail has been constructed through the St Williams Chapel site, which is a scheduled ancient monument and of European importance. Any damage to it is a criminal offence.

The Mousehold Heath Defenders, who look after the site, have reported the damage to the police.

They also want better signage at the site to let people know that it is illegal to ride bikes across the monument or cause any kind of damage, and are hoping to set up an interpretation board in the near future.

Wardens on the heath are now dismantling the trail and filling in the large holes that have been dug.

Margaret Bush, from Mousehold Heath Defenders, said: 'Before the trail was constructed there was just scrub on the site, but now you can see that the soil has been dug up to create the trail.

'We have seen tyre marks from mountain bikes at several points on the trail, mainly at the back of Zaks restaurant, where they can ride down a hill. I think they are trying to join up all the tracks they've made, to make one big trail.

'Obviously, we don't know who is responsible. It's an open site, and can be accessed 24/7.

'But it would take considerable work to dig up the soil there, which is quite firm. The people who did it might have used some tools.'

The Defenders' publicity officer Clare Cohen, from Sprowston, added: 'Unfortunately, the problem is there is no signage as yet to say that St William's is there or that it is an ancient monument and a protected site.

'Our main concern is to let people know that this is a protected site, and it's a criminal offence to cause any damage of any kind to it.

'This a major historical site, of European importance.'

The site of St William's Chapel was founded at about the time of the Norman Conquest and its foundations are believed to still be under the heath. Above ground, the chapel was destroyed during the Reformation.

There is also an unconfirmed story that there is also a monk's house and burial garden under the ground.

The heath is officially cared for by a committee known as the Mousehold Heath Conservators, but in 1972 a new voluntary action group known as the Mousehold Heath Defenders was formed to 'protect Mousehold against encroachment on its area and its environment'.

With representation on the Conservators this group, working with the governing body, has tried to make a significant contribution to the long-term survival of the heath.

According to the Office of Public Sector Information (OPSI), the St William's Chapel site is a Scheduled Ancient Monument – and is protected by the Ancient Monuments and Archaeological Areas Act 1979 (Revised).

Section 28 of the above act states that:- 'A person who without lawful excuse destroys or damages any protected monument – knowing that it is a protected monument; and intending to destroy or damage the monument or being reckless as to whether the monument would be destroyed or damaged shall be guilty of an offence.'

Damage to an ancient monument is a criminal offence punishable by a fine or up to six months in prison.

Do you know of an ancient site in Norwich that needs protecting? Call reporter David Bale on 01603 772427 or email david.bale2@archant.co.uk.