Open warfare as gangs clash in city
As the violence escalated, police feared innocent people would be killed in the crossfire.
Now, with the three men at the centre of the bloodshed jailed for a total of 28 years, police have finally revealed the grim details behind a year-long running battle.
His ex-wife Susan Coleman, 43, and their 23-year-old daughter Astro Coleman had been cleared of involvement in the assault during the trial.
Simpson's jailing followed that of Tant and 20-year-old Marc Webley who received 11 years each in November for shooting Simpson in the back during an ambush near his Granton home.
However, a senior police officer today warned that gang members from both sides remain at large and urged the community to help prevent a repeat of the violent events.
Superintendent Terry Powell, who led the police operation against the ringleaders, said: "Some of these people are in prison but some are still outside. We will be keeping an eye on them. They will not disappear and they may want to establish themselves in the same way."
The trouble flared when a new generation of criminals came up against the old guard in the Granton, Royston, Pilton, Wardieburn and Drylaw areas of the city.
On one side were the members of the "Young Mental Royston" gang who had begun to terrorise the neighbourhood and prided themselves on their ability to inspire fear.
The YMR were fronted by Webley - a thug with more than 60 convictions - who harboured ambitions to establish himself as the crime kingpin of the area.
Among his cohorts was Tant - a convicted rapist at 16 - who followed his friend and leader with blind devotion. The gang was soon embroiled in open warfare over control of the local trade in Class A drugs and cannabis.
The fighting which engulfed much of the north of the Capital for nearly a year was mostly fuelled by their personal clash with Simpson.
Simpson portrayed himself as a "Robin Hood-figure", according to police, and took on the role of protector for the community.
But detectives believe the 46-year-old was also eager to see off the young pretenders who threatened to take over his "patch".
Supt Powell said: "We suspected Simpson was involved with drugs. Webley was very much the up-and-coming criminal who wanted people to think that he ran the area and should be respected. As an older criminal, Simpson started to clash with him in what I would class as a turf war between around 20 people.
"There were more individuals on Webley's side and the majority of stuff was instigated by him. There was a serious violent feud going on between them. A lot of that seemed to be because they were competing over criminal activities in the area.
"We certainly suspected Simpson of being involved in crimes. The feud with Webley and Tant would seem to support that."
In 1993, Simpson had been jailed for six years after being caught with Scotland's largest-ever haul of LSD, worth 31,810. A leading player in the city's underground dog-fighting circles, he told the court he was forced to deal in drugs following the loss of a valuable dog.
Tensions erupted in May 2004 when a series of petrol bombs were hurled at his flat in Granton Crescent.
The assault was quickly followed by the shooting of a 35-year-old associate of Simpson's. The gunman had fired off a volley of bullets through Simpson's flat window from the street below, seriously injuring the victim.
In what was believed to be a retaliatory strike, gunmen targeted a house in Royston connected to the YMR two months later. And that September one of its members was stabbed outside Simpson's incident-prone home.
Police even sent Simpson a letter warning him of Webley's imminent release from a sentence at Polmont Young Offender's Institution in November 2004 in a bid to stem the trouble.
But as the conflict intensified with a series of eye-for-an-eye strikes, it was Simpson who landed in hospital with a gunshot wound to the back. Five bullets were sprayed at him from an automatic pistol by a gunman wearing a balaclava, although only one round hit him.
The High Court heard that on the morning of January 24 last year, two men wearing balaclavas were seen to ride off on a Kawasaki motorbike from near Webley's Wardieburn home.
The hooded riders followed Simpson after he got off a bus near his home and chased him into nearby Granton Terrace.
Tant threatened him with a sawn-off shotgun which had been concealed under his tracksuit top before Webley aimed and fired with a .25 calibre semi-automatic handgun.
Simpson was chased into the common stair of his flat where he was struck by a single round and the assassins made their escape.
The shooting prompted worried police to apply for a court order banning the suspected gangland figure from returning to the property under antisocial behaviour legislation.
The powers forced Simpson to abandon his stronghold for a new address, believed to be in Dalkeith, but only weeks later he launched a revenge attack.
Simpson was travelling with his ex-wife and daughter on a number 14 Lothian bus at Boswall Parkway on March 22 last year when James Tant stepped onboard with his 18-year-old girlfriend, Nicola Meikle.
The older man took the opportunity of their chance meeting to launch a savage knife attack on Tant. His trial heard that Simpson spat out a piece of his victim's ear, as well as inflicting two stabs wounds to his chest.
The jury cleared him of attempted murder but found him guilty of assault to danger of life. Judge Lord McEwan handed him a six-year sentence.
Tant had been called to give evidence during the case but declined to testify, fearful of being branded a "grass" on his return to prison.
Simpson had claimed he was defending his family after his daughter, Astro, had received death threats from the YMR. An artist and singer, she had even taken to wearing a bulletproof vest, the court heard.
Supt Terry Powell said: "He portrayed himself as a sort of Robin Hood-figure who was protecting the community from Webley and his associates.
"His ex-wife and daughter would attempt to portray him that way, as the protector of the community from this gang, someone who helps people out.
"Some people in the area might even say there was some truth in that. But that simply wasn't the case.
"He's a very violent person as his latest convictions shows. He stabbed a man on a bus and bit part of his ear off. He would claim to be helping his neighbours, but carry a knife and try to kill someone with it.
"Simpson knew that Webley had been targeting him and knew he was one of those responsible for the shooting. That's why he launched the revenge attack on Tant - who was really one of Webley's hangers-on - while he was on the bus."
Supt Powell said that the force had derived "a great deal of satisfaction" from the three convictions, but asked local residents to continue to co-operate with police.
He added: "Three violent criminals have been put away and the positive impact on the community has been significant. We can't always know what's going on so we need residents to help us. Now they've seen the results from that kind of cooperation."