The conservation group is calling for Haringey and Barnet councils to impose archaeological conditions one building works

�Historically important archaeological sites in Highgate may have been lost due to councils failing to impose excavation conditions on new developments, an expert warns.

Barnet and Haringey Councils stipulate that the village is an area of archaeological interest. But neither demands excavation work on all new developments.

Archaeologist Michael Hammerson claims this failure is likely to have led to many important artefacts being lost – significantly diminishing peoples’ historical knowledge of the area.

A member of conservation watchdog, The Highgate Society, Mr Hammerson is calling on both councils to introduce stricter conditions.

“I have absolutely no doubt that we have lost some pretty big sites,” he said.

“We are very rarely going to find anything worth something – but it is important evidence of our early history.

“If you destroy an archaeological site, it is like going into the British Library, taking out old documents which have never been read and destroying them.”

“I think, from both local authorities, there is a lack of interest in grasping what archaeology is all about and the potential of this area.”

Mr Hammerson made his comments just days after finishing work excavating part of Highgate School in North Road. The school is being expanded.

During the dig, he found evidence of medieval occupation and the remains of 16th century kilns.

The kilns are believed to have been used to produce bricks to build the school.

Highgate School opened in 1565 and is one of the oldest in England.

But many more treasures remain either hidden or lost forever because of insensitive developments, Mr Hammerson believes.

Highgate is steeped in history and was once the site of a medieval hunting park.

A Bronze Age burial ground stands at the top of one of the meadows in nearby Hampstead Heath.

But Mr Hammerson also warns that pending Heath works to prevent its dams and ponds from flooding could mean the loss of important historical remains unless archaeological excavations are carried out.

Barnet and Haringey Councils both consult English Heritage on new developments within Highgate and enforce archaeological conditions when advised.

Spokesmen for both councils said that their policy was robust.

But Haringey added that the council would be happy to discuss amendments.