The human remains of a prestigious British Jewish dynasty risk being dug up after their graves have been levelled by a bulldozer, unless a last remaining family heiress and the Jewish community can win their claim to the land by Friday.

The Bright family mausolea sit in Rodmoor in the Peak District near Sheffield as the lavish private Jewish burial ground for the wealthy jeweller and cutler family.

The Brights were founding members of Sheffield's Jewish community and drove the Sheffield steel trade, and their unique beehive-shape stone tombs were the final resting place for 15 members of the dynasty dating back 100 years.

But in December the tombs were demolished by adjacent landowner Anthony Bevis who claimed the graves were empty and applied to the Peak District authorities to build his own family tomb over the Jewish site.

He had previously used some of the tombstones to build an extension to his house. Mr Bevis will nevertheless have the right to seek title over the land based on a squatters' law unless it is challenged within 12 years, a period which closes on August 24.

Official council documents have now emerged proving Jewish human remains still lie buried on the site.

Just days before their tombs were demolished English Heritage said Rodmoor should be preserved as a Jewish heritage site.

But the Peak Park Authority said it was not currently taking action against Mr Bevis and local police have refused to press charges of criminal damage.

Cymone De Lara Bond, a fifth-generation granddaughter of the Bright dynasty, said the Sheffield Jewish community had dragged its feet to provide vital evidence which will prove the historic burial ground is still under ownership of the community.

“I want the Jewish community to sit up and take responsibility. From Friday he could dig up those bones and dump them anywhere, and that cemetery could be wiped off the face of the earth.

“It's been a nightmare. I feel so saddened and disappointed. I haven’t got the support from Jewish community that I would have hoped for,” she said.

Mrs De Lara Bond's solicitors have contacted the Board of Deputies, which can help undermine Mr Bevis' claim to the land by providing evidence that Mr Bevis was not given the land.

But the Board, which has a limited company which preserves 80 abandoned Jewish cemeteries, said it was not in a position to fight land ownership battles.

The BOD's Colin Spanjar said: “No one has ignored this. We are trying to put pressure on the Land Registry Office to delay a decision until we can get documentary evidence that the land was not given to the man claiming a title.

"Our solicitors are on the case. There is also a question we have on why the local authority would allow something to be built over a Jewish cemetery. The Board will ask why they are ignoring the fact that this is a Jewish cemetery and ignoring Jewish law.”

Dr Sharman Kaddish from Jewish Heritage UK said the case presents “an open invitation for a developer anywhere in the UK to appropriate any Jewish cemetery and desecrate it and build all over it.

"There is a worrying problem in planning law which doesn't consider religious considerations, which is also a problem for Jewish cemeteries at risk.”