Lord Lucan: Murdered nanny’s son searches for missing killer

Mr Berriman’s quest to trace Lucan began with the discovery of a brown envelope in a chest of drawers belonging to his adoptive mother.

Three years after she died of cancer, he plucked up the courage to open it.

It was stuffed with photos, documents and newspaper clippings, revealing the identity of his birth mother.

On making the devastating discovery, Mr Berriman said he was “desperate” to find out as much information as he could about Ms Rivett’s murder, and as quickly as possible.

“The chances of you being adopted and finding out your mother is one of the biggest murder mysteries of all time is just unbelievable,” the builder from Hampshire said.

“She’s the mother I never knew, but that makes no difference.

“Sandra is still my mum and I will do the best I can for her.”

Graham Forsyth was a detective sergeant with the Met Police when he found Ms Rivett’s body in the basement of Lucan’s house.

“In the dark, you could see there was a sack… there appeared to be an arm hanging out of it,” he said.

The seventh Earl of Lucan’s blood-soaked car was later found abandoned in Newhaven, East Sussex.

Despite never being tracked down, an inquest jury declared him to be the nanny’s killer in 1975.

Lucan was born Richard John Bingham in 1934 and was officially declared dead by the High Court in 1999.

While most of Lucan’s friends and family insisted he had taken his own life, Mr Berriman was adamant he was still very much alive – and on the run.

“There is also no actual proof that Lucan was dead so he could still be alive,” he said.