She left her office for an appointment with a Mr Kipper and was never seen again. No body was ever found and no one has been charged.

"We have received certain information from a member of the public relating to the disappearance of Suzy Lamplugh," a Scotland Yard spokeswoman said.

"We will follow up that information in the same way we would follow up any new information.

"The investigation into the disappearance of Miss Lamplugh is still open."

Murderer 'is in prison'

The Suzy Lamplugh Trust, set up by her mother, said it believed that her murderer is in prison for the murder of another woman.

Police have questioned Bristol car dealer John Cannan who is now serving a life sentence for another murder. He has always protested his innocence of the Lamplugh murder.

A 1995 book said Michael Sams, who murdered prostitute Julie Dart and kidnapped property consultant Stephanie Slater, also killed Ms Lamplugh, but police were not convinced by the theory.

In a statement the trust said: "Whilst it would be a relief to know exactly what happened to Suzy, the family now focuses its activities on ensuring other people do not suffer the same fate."

The Suzy Lamplugh Trust, founded five months after her disappearance, aims to help working women avoid becoming crime victims.

Recently it campaigned for licensing and regulation of minicabs in London.

After an extensive but unsuccessful search, the Suzy Lamplugh inquiry was scaled down, and she was officially declared dead in 1994.