Seven men are facing life sentences after being convicted of murdering Hells Angel Gerry Tobin, who was shot dead as he rode his motorbike along the M40 in August 2007. The killing took place against the backdrop of a global feud between the Hells Angels and a rival biker gang, the Outlaws. But what started the bad blood?
By Chris Summers
The Hells Angels are the world's most infamous motorcycle club. There are around 2,500 full members - who are allowed to wear the club's "patches" on their backs - across North America, Europe and Australasia and hundreds more "prospects" and associates.
But in the 1960s and 1970s several other gangs emerged who would become their sworn enemies. They included the Bandidos, the Outlaws, the Mongols and the Pagans.
Julian Sher, a Canadian investigative journalist and author of two books on biker gangs, told BBC News: "These other gangs hate the Hells Angels... because they are so dominant."
He said: "Sometimes it is a turf war over drugs or the sex trade but often it's just to do with the pride of the patch. A lot of it is just to do with ego and testosterone; it's about macho chest-thumping and who is the toughest pitbull in the junkyard."
Between 1994 and 1997 the Hells Angels and Bandidos across Scandinavia fought what was described as the "great Nordic biker war".
At least 11 people were killed and dozens injured in a bloody power struggle involving car bombs, machine guns and even anti-tank rockets stolen from a Swedish army depot.
The "war" ended in an uneasy truce.
The feud between the Hells Angels and the Outlaws - which led to Gerry Tobin's murder - dates back nearly 40 years.
In 1969 the wife of an American Hells Angel is believed to have been raped by an Outlaw, who was subsequently beaten up and almost killed in revenge.
Hells Angels - formed in California in 1948. Now has 235 chapters around the world. Sometimes referred to as the 81 from the letters of the alphabet (HA = 81).
Outlaws - formed in Illinois in 1930s. Have spread to Europe and are bitter enemies of Hells Angels.
Bandidos - formed in the US but are now very strong in Scandinavia, where they clashed with the Hells Angels.
Mongols - founded in California in the 1970s by Hispanic bikers refused entry to the Hells Angels. They have spread worldwide.
Pagans - formed in 1959 in Maryland but have spread throughout US and abroad. Allied to the Outlaws.
Rock Machine - French-Canadian gang who were involved in a bitter war with Hells Angels in Quebec in 1990s. Allied to Bandidos.
The Outlaws hit back by shooting dead three Hells Angels, whose bodies were dumped in a quarry in Florida.
The hatred has grown ever since and has spread across the globe wherever the two have formed chapters, or clubs.
In 1987 the British wing of the Hells Angels wanted to hold an annual get-together and needed a venue.
They chose the former Long Marston airfield, an isolated site a few miles outside Stratford-upon-Avon in Warwickshire, which was to become home to the Bulldog Bash.
Unfortunately the Coventry and Warwickshire chapter of the Outlaws believed the site was on their turf and their resentment grew over the years.
In Britain several smaller clubs are allied to the Hells Angels.
At this year's Bulldog Bash there were patches on show belonging to the Barbarians, the Confederates, the Devil's Disciples, The End (from Hampshire) and The Predators (from Somerset).
Other gangs are allied to the Outlaws or the Bandidos. In 1998 two bikers were left dead when 40 Hells Angels attacked a gang called the Outcasts - allies of the Outlaws - at the Rockers' Reunion gathering in Battersea, south London.
Ronald "Gut" Wait, vice-president of the Hells Angels' Essex chapter, was eventually jailed for 15 years for conspiring to cause grievous bodily harm.
Later that year the Outlaws threatened to bomb the Bulldog Bash and in 2000 the Coventry Outlaws became official affiliates of the American Outlaw Association.
Vow of silence
Tension between the gangs spilled over in August 2001 when a Hells Angel was shot three times in the leg as he left the Bulldog Bash.
The shooting, on the M40 motorway, was almost identical to the attack on Gerry Tobin but in this case the victim survived. He refused to make a statement to the police, as is customary with biker gangs.
Globally the feud has spiralled in recent years.
At this year's Bulldog Bash this special tribute bike was on display
In 2006 an Outlaws chief in New Hampshire, Christopher Legere, was convicted of murdering a man who was wearing a Hells Angels T-shirt.
Later that year two Canadian Hells Angels shot several Outlaws at the world's biggest biker rally in Sturgis, South Dakota.
Early in 2007 the UK chapter of the Outlaws took over the European "presidency" and might have felt under pressure from peers to up the ante against the Hells Angels.
Mr Sher believes this may have been a key factor in the killing of Gerry Tobin, who was shot as he returned home from the Bulldog Bash.
His murder on a busy motorway on a Sunday afternoon was clearly a signal to bikers across the world.
Shortly after his killing an Outlaws clubhouse in Scandinavia was attacked, and one person was killed.
Sean Creighton tried to take the rap for the whole gang
There were other incidents in Britain, some of which cannot be reported for legal reasons.
Police feared another violent incident at this year's Bulldog Bash and they opposed the renewal of its entertainment licence. The local council overruled them and it passed without incident.
Hells Angels in this country insist they are simply motorbike enthusiasts and not a criminal gang and they accuse the police of exaggerating the idea of a feud.
One Hells Angel told the BBC there was not a jot of evidence to support the police's assertion that they had planned to take revenge for Gerry Tobin's death.
When the trial began one of the Outlaws, Sean Creighton, pleaded guilty and basically sought to take the rap for the whole gang. But it did not work and six other men were later convicted.
Police hope there will be no further bloodshed.
But Mr Sher is not hopeful and says: "A lot of people in Britain have this idea of bikers as loveable rascals; they took part in the Golden Jubilee parade and their PR is often good.
"But whenever these rival gangs compete there is violence."