The mystery of what happened to Lord Lucan is being brought to the small screen 40 years after the notorious aristocrat disappeared - with Rory Kinnear in the lead role.

Rory will play the peer who vanished after his family's nanny, Sandra Rivett, was found dead at the home of his estranged wife in London's Belgravia in 1974 after being bludgeoned with a lead pipe.

The attacker also turned on Lady Lucan, beating her severely before she managed to escape and raise the alarm at a nearby pub.

Lucan's car was later found abandoned and soaked in blood in Newhaven, East Sussex, and an inquest jury declared the wealthy aristocrat the killer a year later.

What happened to Lucan remains a mystery and he was officially declared dead by the High Court in 1999 but there have been reported sightings of him as far afield as Australia, Ireland and South Africa.

The two-part ITV drama is based on John Pearson's book The Gamblers, which claims Lucan's high-rolling friends who gathered at the Clermont Club in Mayfair, central London, and included Sir James Goldsmith and John Aspinall, spirited him out of the country after the murder.

Former Doctor Who star Christopher Eccleston will play Aspinall and the cast also includes Michael Gambon.

The show is written by Jeff Pope - the man behind last year's hit true-life crime drama Mrs Biggs - and filming starts later this year.

Executive producer Francis Hopkinson said: "This extraordinary and tragic event has fascinated people for 40 years. Jeff Pope's script, based on John Pearson's book The Gamblers, brings new insight and revelations, which will surprise the audience. We are delighted that a top cast and director have come together to tell this story."

Rory recently dismissed reports that he could take over from Matt Smith in Doctor Who.