In a campaign that made international headlines he rubbed shoulders with world famous stage and screen star Vanessa Redgrave and her late brother Corin, who both threw their weight behind the travellers' battle to stay put in Essex.
He also made repeated trips to Parliament, the European Parliament and United Nations to try to get support from MPs and international diplomats.
But during a lengthy criminal prosecution which ended yesterday, he was exposed as being at the heart of an international crime gang.
A court heard many of his co-defendants were related to him and linked to Dale Farm, its sister traveller site Smithy Fen in Cottenham, Cambridgeshire, and conventional houses in Wolverhampton and in Rathkeale, in the Republic of Ireland.
Fourteen members of the organised crime gang, dubbed the Rathkeale Rovers due to their connections to lavish properties in the Irish town, have now been convicted over their roles in stealing artefacts worth up to £57m from museums and an auction house in 2011 and 2012.
Items included Chinese jade and rhino horn, which is more valuable pound per pound than gold, were stolen in Cambridge, Durham, Norwich and Lewes, East Sussex.
The case can now be reported after the final four gang members, described as some of the "generals" who helped plan and oversee the audacious crimes, were convicted at Birmingham Crown Court following a two month trial.
Eight others were convicted at earlier hearings, with two pleading guilty to their crimes.
The crime wave involved two thefts and an attempted theft at Durham University Oriental Museum, plus incidents at Gorringes Auction House in Lewes, Norwich Castle Museum and the Fitzwilliam Museum in Cambridge.
Chinese artefacts worth up to £15m were stolen from the Fitzwilliam Museum in April 2012.
The court heard other items were valued at £17m but detectives estimated the total value could have reached £57m due to a "booming" Chinese market.
Detective Superintendent Adrian Green, of Durham Police, said the thefts "dwarfed" the Hatton Garden bank vault raid in which items worth about £14m were stolen.
He said: "If you think the Hatton Gardens break-in was big, this will blow that out of the water."
The valuables were then hidden in a field, but the defendants claimed to have later forgotten where. However, they were still found and returned.
On April 13, 2012, 18 jade artefacts worth £15m were stolen in a raid on the Fitzwilliam Museum and have never been traced.
Five months later three men working for the gang were jailed and a boy of 16 was given a detention order.
Although the actual thieves responsible for the jobs were earlier jailed, police said it became apparent an international organised crime gang planned and commissioned them.
If you think the Hatton Gardens break-in was big, this will blow that out of the water.
Raids took place in Rathkeale the same day.
A four-year covert national investigation - operation Griffin - led by officers from Durham and Cambridgeshire and supported by the National Crime Agency led to the prosecution.
Sheridan, who moved to Smithy Fen after the 2011 Dale Farm eviction, was arrested at the Cambridgeshire site during the raids.
In the years before the Dale Farm eviction he acted as a spokesman for the site and regularly met with police, council chiefs and MPs to try to argue for a stay of execution.
He denied conspiracy to burgle but was convicted at a trial last year.
His dad John "Cash" O'Brien, 68, of Fifth Avenue, Wolverhampton, was convicted of the same offence.
John O'Brien junior and Richard "Kerry" O'Brien are his cousins, while Daniel O'Brien and Michael Hegarty are married into the extended family.
Both Sheridan and his dad have been twice jailed in 2004 and 2006 respectively for organised cigarette smuggling.
John O'Brien senior's brother businessman Richard "Kerry" O'Brien was arrested at his Rathkeale home, but never charged.
He has since set up a blog alleging he is harrassed by the authorities.
In the weeks before the eviction Sheridan made the audacious offer to Basildon Council to get every one off the site without the need for bailiffs for a £6million fee he said he would use to buy alternative homes - the offer was rejected.
The eight other defendants included Donald Chi Chong Wong, 56, of Clapham Common South Side, London, described in court as the "fence" who often travelled to Hong Kong.
The others were Alan Clarke, 37, of Melbourne Road, Newham, London; Patrick Clarke, 33, of the same address, Paul Pammen, 49, of Alton Gardens, Southend, Essex; Danny Flynn, 45, of Smithy Fen and Ashley Dad, 35, of Crowther Road, Wolverhampton, who has gone on the run since his conviction.
Robert Gilbert-Smith, 28, of no fixed address, pleaded guilty to his part last March and has served his sentence.
Terence McNamara, 46, of Marquis Street, Belfast, pleaded guilty at the beginning of the final trial on January 4.
The gang are due for sentence this spring.
The 'Rathkeale Rovers' Irish traveller gang whose robbery spree amassed a £57million haul – FOUR TIMES bigger than Hatton Garden raid
- 14 men linked to an organised crime gang are found guilty of plotting theft
- Four convicted today of helping plan break-ins in Cambridge and Durham
- Exhibits stolen there may have fetched £57m on Chinese auction market
- Trial can only be reported today due to offences by the 'Rathkeale Rovers'
THE TINY IRISH TOWN BOUGHT UP BY 'GUCCI TRAVELLERS' WHO RETURN HOME EVERY YEAR TO FLASH THEIR CASH AND SPEND ILL GOTTEN GAINS
TIMELINE: RHINO HEAD 'WAS TOO HEAVY TO STEAL'
RHINO HORN TARGETED BECAUSE OF 'ABSURD' BELIEFS IN HEALING
- Basil ‘the evil clown’, wore his disguise throughout Hatton Garden heist
- He seemingly vanished without a trace after the £14million burglary
- Detectives have four suspects but the identity of Basil remains a mystery
- Basil believed to be in Panama, with another figure from British underworld
- Flying Squad, Adams family and friends of Hatton Garden gang after him