A computer engineer is facing extradition from Britain to Italy this morning to start a 26-year prison sentence for the murder and kidnap of a wealthy Italian aristocrat 30 years ago.

A "supergrass" implicated Enrico Mariotti, 66, of Burgess Hill, in the abduction and killing of Massimiliano Grazioli, who was snatched from his BMW by a gang outside Rome in November 1977.

The murder of Duke Grazioli, who had substantial media interests and whose family had been millers to the Vatican, was said to have been a notorious and highly publicised crime.

After his kidnap, the family of Duke Grazioli received a ransom demand for 10 billion lira.

Following four months of negotiations with the kidnappers, his son Giulio, finally paid 1.5 billion lira (£750,000) in March 1978, throwing the cash in a bag from a motorway bridge after the gang below gave agreed codewords.

But the duke was nonetheless killed, having apparently recognised the face of one of his kidnappers. His body has never been found.

Italian Mariotti, who has lived in the UK since 1993, was accused of supplying inside information about the aristocrat and his family and orchestrating the kidnapping.

He denied involvement but was convicted in his absence to 24 years imprisonment by the Italian authorities in 1995 on the strength of testimony by a "supergrass". His sentence was subsequently increased to 26 years following a review in 2000.

Mariotti, a grandfather of four, is expecting an officer from Scotland Yard to take him from his home in Burgess Hill, to board a flight to Italy with no hope of any further legal challenge.

He has resigned from his job with an IT company in Sussex called Pav IT, and will leave behind his partner Christine Paterson to start his sentence, which he claims to be a miscarriage of justice.