Two gravestones have been mysteriously altered - and no one knows how or why.

Relatives were shocked to find that headstones at the graves of Joseph and Mary Morris, who have been buried side-by-side in Edmonton Federation Cemetery for 70 years, had been altered and given different wording.

David Harris, a great-grandchild, made the discovery when he visited a week ago.

Mr Harris said: "They've been completely renovated. The stones have a different facade and the wording is different. They didn't used to be totally joined as they are now, and there were cracks which had been filled in.

"I contacted other family members and no one knew what had happened. It's so strange. There are no direct surviving relatives other than one granddaughter, and she's 94."

Richard Selby, another great-grandchild, said the original tombstones bore the inscription "Joel Joseph Morris and Mary Morris, also known as Mary Joseph". Now, they simply say "Joseph Morris and Mary Morris".

Tom Zelmanovits, who is in charge of the cemetery, said: "I'm not sure who's changed the headstones. It's certainly not a recent change."

He confirmed the archives list the original wording but said that there was "no record of any authorisation for the changes. Any work would require an application, and we have none".

He added: "Things like this do not happen. We have a foreman, we have staff on the ground, including an authorised stonemason who deals with any alterations to stones. If what they say is correct, it's concerning."

The Morrises were among hundreds of thousands of Jews who emigrated from Poland to East London in the late 19th century.