George Bingham had applied to take up his father's place in the House of Lords, which has been vacant since Lord Lucan vanished almost 25 years ago.

But the Lord Chancellor, Lord Irvine of Lairg, turned down the application because he was "not satisfied" by his case.

Lord Irvine: "Not satisfied"

The decision means George, who uses the courtesy title Lord Bingham, will never sit in the Lords and may have to wait years before he can formally inherit the title.

His father, Lord "Lucky" Lucan, disappeared on 7 November 1974, the night nanny Sandra Rivett was found battered to death with a lead pipe at the family home in the exclusive Belgravia area of London.

While there have been numerous reported sightings of him around the world, his fate has remained a mystery.

Lord Bingham has given up his job as a City banker to write a book about his father.

A spokesman for the Lord Chancellor's Department said: "I can confirm that the Lord Chancellor did not authorise the writ of summons to George Bingham on the ground that he was not satisfied that his case had been made out."

It is understood that Lord Irvine felt that technical details, such as the lack of a death certificate, left him with no choice but to reject the application.