A man was jailed for 18 months yesterday for his part in a botched raid on the Castle Museum.

Patrick Kiely, 29, who is serving a six-year sentence for raiding up to �15m worth of jade from the Fitzwilliam Museum in Cambridge, attempted to take the rhino head from the Norwich museum on February 20 this year.

But the plot was foiled by alert staff who forced the gang, clad in balaclavas, to drop the head, worth up to �500,000, as they fled.

The four men escaped in a dark saloon car which was spotted near Argyle Street off Rouen Road.

But police later caught one of the culprits - Nihad Mahmod - after they found his finger prints on fake number plates which he tore off the car and left at the side of the road.

Prosecutor Peter Gair told the court the gang of four smashed the glass case as they attempted to steal the artefact.

Mahmod, 21, was jailed for two-and-a-half-years in July, while two other men arrested over the attempted theft have been released.

Sentencing Kiely at Norwich Crown Court, Recorder of Norwich, judge Peter Jacobs told him he had targeted part of our heritage.

He said: 'To steal from museums shows a complete contempt.

'You take something away from us all. You diminish us all when you steal in this way.'

Rebecca Hill, mitigating, said Kiely, who admitted the attempted theft, had been forced into taking part in the raid by men threatening his family.

And after the failure of the raid, she said he was then forced to take part in the Fitzwilliam raid on April 13.

But Judge Jacobs dismissed the mitigation as 'twaddle'. 'If you think I am going to buy that sort of twaddle, you are talking to the wrong man,' he said.

Kiely of Eleanor Street, Bow, was identified from the castle's CCTV by Metropolitan Police officers.

The 18-month sentence will be served on top of the six years for the Fitzwilliam theft.

The museum has since replaced the rhino horn on the Victorian specimen with a replica.

Rhino horns are prized in China for their supposed aphrodisiac qualities.

Lord Nelson artefacts worth �36,000 were also stolen from the museum in February.