A jury convicted four of the gang’s “generals” who helped to plan and oversee a string of offences, including break-ins at Cambridge’s Fitzwilliam Museum and Durham’s Oriental Museum in 2012.
John “Kerry” O’Brien Jr, aged 26, Richard “Kerry” O’Brien, aged 31, Michael Hegarty, aged 43, and Daniel “Turkey” O’Brien, aged 45, were found guilty after a trial which could not be reported because of similar offences committed by travelling criminals dubbed the ‘Rathkeale Rovers’.
The two-month hearing at Birmingham Crown Court was told that 10 other men had previously been convicted for their parts in the conspiracy, which included a bungled attempt to steal a rhino head from Norwich Castle Museum.
Although jurors heard that exhibits stolen in Durham and Cambridge were valued at around £17m, detectives believe they might have fetched up to £57m on the “booming” Chinese auction market.
Members of the gang also masterminded an offence at Gorringes Auction House in Lewes, East Sussex, and organised the disposal of stolen artefacts.
At least eight of the men convicted after a four-year international police inquiry have family or business links to Rathkeale, Co Limerick.
The latest trial was told a computer used to make incriminating internet searches was found at a house in the town.
Other defendants aged between 28 and 68 — from Cambridgeshire, London, Southend-on-Sea, Wolverhampton, Kent and Belfast — either admitted the offences or were found guilty by jurors.
They included six members of the same Rathkeale family, travellers’ rights campaigner Richard Sheridan, and Donald Wong, a London-based “fence” who made frequent trips to Hong Kong.
A previous trial heard that Sheridan, a former spokesman for the Dale Farm travellers’ encampment in Essex, was seen in the company of Wong shortly before police found £50,000 in cash in the boot of a car.
Sheridan, aged 47, of Water Lane, Smithy Fen, Cottenham, Cambridgeshire; Wong, aged 56, of Clapham Common South Side, London; and Richard O’Brien, of Dale Farm, Oak Lane, Billericay, Essex, denied taking part in the plot between September 2011 and August 2012.
Hegarty, John O’Brien and Daniel O’Brien, all of Orchard Drive, Smithy Fen, also denied any involvement in the offences but were unanimously convicted.
None of the 18 jade exhibits stolen from the Fitzwilliam Museum in April 2012 have been recovered, but a bowl and figurine stolen in Durham were found.
Derbyshire chief constable Mick Creedon, the national policing lead for organised crime, said: “This case starkly demonstrates the level of threat, the lengths criminal gangs will go to and the importance of law enforcement agencies sharing intelligence and working together.”
One of the men convicted has already been jailed and served his sentence. The other 13 offenders will be sentenced in April.