It was a hot summer’s day in late June 2003, and Stewart Boyd was making his way back to his home in the south of Spain.

The 40-year-old had just driven to Malaga Airport on the Costa Del Sol with his daughter Nicola and three-year-old daughter of his girlfriend to collect a friend of Nicola’s who had just arrived from Scotland for a summer break.

After leaving Malaga airport, Boyd inexplicably lost control of his hired Audi TT crossing the central reservation of the A7 near Torremolinos colliding with a BMW 525 coming in the other direction.

Boyd, from Nitshill, Glasgow, was killed on impact as was his 21-year-old daughter, her friend, also 21, and his girlfriend’s daughter.

Two Spanish tourists in the second car, a 42-year-old man and his 13-year-old son, also died instantly in the crash.

In the immediate aftermath, Strathclyde Police contacted their Spanish counterparts to establish the cause of the head-on collision, which also left Boyd’s Audi burnt beyond recognition.

`The reason was simple. Stewart Boyd – nicknamed Specky – was no ordinary visitor to the island.

He was a member of Glasgow’s criminal underworld with links to major crime figures of the time, including Tam “The Licensee” McGraw.

School pals gave Stewart Boyd his “speccy” nickname when he started wearing glasses as a child – but as an adult, no-one dared use it to his face.

The spectacles he wore gave him the air of a bank manager but nothing could be further from the truth.

He had been at the centre of a violent turf war gripping the security industry back home with convictions dating back more than 20 years.

Before his move to Spain he was said to run a massive network of drug dealers across the Southside of Glasgow.

It was also claimed he had an involvement in the deaths or disappearances of as many as nine criminal figures over the years.

For obvious reasons, the Strathclyde officers wanted to make sure the crash was an accident and not some carefully orchestrated reprisal.

Strathclyde were told that there was nothing suspicious about the fatal road crash, However, they were asked to supply dental records of the four Scottish victims, including Boyd, because the condition of their bodies made identification possible.

One Spanish paramedic who attended the crash scene said at the time: “It was horrible, a nightmare job for us. The bodies were burned beyond recognition.”

While one local officer told reporters that it looked as if a bomb had gone off.

Though Boyd was a man of violence, the nature of his death shocked friends and family.

One pal said at the time: “Stewart was no angel. There are kids involved in this and it makes it so hard to take for everyone.

“If he had been shot in the street then you could have understood it because that’s the life he led. But for it to happen to six people including his daughter is a tragedy for all concerned.”

Boyd first came to police attention while running a security firm in Ferguslie Park, Paisley, in the late 1980s – then one of the most deprived parts of Britain.

In 1996, Mark Rennie, a 26-year-old local drug dealer who owed him money was shot dead.

One of Boyd’s associates Stewart Gillespie was convicted and handed a life sentence.

Gillespie was also convicted with two associates of an earlier attempted murder on Rennie in 1995.

Meanwhile, Boyd had fled to Spain but eventually returned to stand trial on a charge of conspiracy to commit the murder.

He however walked free from the dock after the jury found him unanimously not guilty.

Boyd’s narrow escape from justice only served to bolster his ruthless hardman reputation on the streets and as a man to be feared.

Four years after Rennie’s murder, in September 2000, Boyd was accused of intimidating a prosecution witness in an extortion case at Glasgow Sheriff Court.

It was claimed that he approached the man in the court building and warned him not to give evidence that day against a security firm owner, who was accused of extortion.

However, the exchange was witnessed and caught on CCTV which was in the courtroom at the time.

The witness did not give in to the threats and gave evidence.

However, the security firm boss, who was on trial, walked free on a not proven verdict.

The following month the same witness’s house in Shawlands was sprayed with bullets, though no-one was injured. No-one was arrested either.

At the end of the extortion case, a warrant was issued for Boyd on the intimidation charge but he went on the run again travelling between Scotland and Spain before he was finally arrested in Aviemore.

In July 2001, he pled guilty at Glasgow Sheriff Court and was sentenced to 18 months in prison.

After his release Boyd set up a base in the Andalucian town of Mijas near Malaga. He was living there on the day that he died.

Boyd was laid to rest in a cemetery in Neilston, East Renfrewshire, following a service at his father’s home in Priesthill on the Southside of Glasgow with hundreds of mourners lining the street outside.

Shortly after his death, it emerged that he was at the centre of a massive drug surveillance operation by the London-based National Crime Intelligence Service (NCIS).

While living in Spain he had been splashing the cash which had brought him to the attention of the authorities.

His favourite haunts included a Hugo Boss store in Puerto Banus and exclusive restaurants in the Marbella area.

One NCIS officer said at the time: “We were well aware of who Boyd was and his involvement in drugs and organised crime. He was the subject of our attention in the days before he died.”

It was also rumoured that his death might not have been an accident but a cold-blooded gangland killing instead.

It was said Boyd had done business with the Russian Mafia and had failed to pay them for a £2.5 million shipment of cocaine thus resulting in the hit.

Investigators probing the crash which killed Boyd – which happened on a straight road in good conditions – said the ferocity of the deadly fireball was unusual.

While a post-mortem showed no trace of drink or drugs in Boyd’s body.

It was later claimed that Boyd had a laptop showing £15m worth of assets belonging to Tam McGraw.

It was said that McGraw and other underworld figures had trusted Boyd to launder their substantial assets abroad.

But after his death, the laptop went missing, leaving the criminals unable to get at their money.

Details of Boyd’s own dealings were also included on the computer, along with the business of at least two other major gangland figures.

News of the existence of the laptop came to light when McGraw died in his home in Mount Vernon, Glasgow, in 2007 from a heart attack.

It’s not known if the laptop was ever found.

A source said the time said: “Irrespective of what some people thought of him, Boyd was very well regarded in some quarters and top figures – including McGraw – entrusted him to do their ‘banking’ for them.

“He got a lot of their money out for them and then managed to launder it while keeping forensic records of all the deals.

“But he died so suddenly and unexpectedly that no-one really knew what happened to the computer.”

Despite suggestions of a Russian mafia link to his death, his step-sister Jeannie McDougall, to whom he was close, always believed the answer lay closer to home.

In an interview in 2010, the 45-year-old said: “There is no way that Stewart just crashed the car.

“He was a very, very careful driver, to the point where everyone used to laugh at him about it. He was a big player, so he knew to never attract the attention of the police over some petty driving matter.”

Jeannie added: “But I also know he had those children in the car so I know he would have been extra, extra careful.

“We know he had a slow puncture and he had been told repeatedly to fix it, but even a tyre blow would not have explained away that crash. It was far too horrific.

“The car had basically exploded.

“I am convinced that someone tampered with his car and made sure he never came back to Scotland again.”