Professor Hassan Ugail said he had no idea he was working on the case of the famous aristocratic fugitive when he was asked to compare eight images sent to him by Neil Berriman, the son of Lord Lucan's murdered nanny Sandra Rivett.

The Professor of Visual Computing at the University of Bradford said he did not know which of the photos were already verified pictures of the missing murder suspect, who will be 87 if alive, and an elderly man said to be living in the Brisbane area.

But he said his powerful facial recognition algorithm, developed during the past 20 years, left very little doubt they are all pictures of the same person.

"I compiled the results and then I sent it to him (Mr Berriman) without even knowing anything about this entire case," Prof Ugail said.

"Afterwards, he actually rang me and said 'do I actually realise who this is?'. I said 'not really' as I am not particularly familiar with Lord Lucan's photos."

The professor said the results were "startling".

"They all are kind of saying this is the same individual," he said.

"Having a result like this actually calls, probably, for an investigation."

Prof Ugail said his algorithm compares 4000 different points on faces, including the size of features down to individual pixels and skin tones, to make comparisons in images that far outperform the human eye.

The program has used artificial intelligence to learn for more than a decade from countless faces.

Prof Ugail has used it to help in a range of high-profile cases, including identifying Russian suspects in the Salisbury Novichok attacks, the assassination of journalist Jamal Khashoggi and an investigation into a Nazi war criminal living in the UK.

"I have to say that in all the cases that I have worked with, the high-profile cases, nobody has come and questioned it," he said.

"I'm fairly confident about my algorithm in that sense. It's fairly foolproof technology."

Prof Ugail said Mr Berriman contacted him out of the blue, saying he was "investigating a matter which is very close to his heart".

"I hope that he's got some closure based on this. I don't exactly know how this is going to go forward," he said.

Mr Berriman told The Mirror: "I've spent nine years trying to prove this man is Lucan. Now, with this new scientific information, the police must act. This isn't emotion. It's fact."

Monday marked the 48th anniversary of the day in 1974 when Ms Rivett was killed, with Lord Lucan - the main suspect in the murder - vanishing shortly after.

Lady Lucan, who was also attacked, identified her husband as the assailant but he had already disappeared.

Since 1974, the Lord Lucan case has become shorthand for every mystery involving missing people who may be alive or dead.

Australian Associated Press