A man has revealed what it was like to be an ‘undercover police officer” in Glasgow in the 80s. 

Simon McLean claims he has worked undercover for the last two decades and gave curious users the chance to ask him anything about his career.

He took to Reddit ahead of the launch of his police memoir 'The Ten Percent' and social media users were left fascinated by his 40-years of experience. 

The retired detective revealed he joined the Serious Crime Squad as a murder detective and then as a surveillance expert.

But he had not always planned to become a cop he explained. 

"Basically, I became a copper because I had messed up my apprenticeship in the Clyde shipyards.

"As a lad I'd also dreamed of being a footballer (ha, who didn't) but had a bad injury so that was quickly quelled."

READ MORE:Glasgow commander Hazel Hendren tells of policing Govanhill to her fears over murdered Karen Buckley

While his cases have spanned across countless areas, he revealed the Lockerbie plane bombing was one of the hardest to stomach. 

He wrote: "The worst case I ever worked on has to be the Lockerbie plane bombing. It was just horrific.

"I was only one of many detectives on the investigation, but the sadness and horror will live with all of us forever. Bodies and wreckage everywhere, spread over a vast area.

"All of the luggage and personal belongings. And, of course, wondering what it must have been like for the passengers falling 36,000 feet to their deaths.

"We were told that they would have been unconscious quickly due to the altitude and the temperature, but we always felt that was told to us just to keep us sane."

Mr McLean also revealed there were a few time he simply did not believe the outcome of a case. 

"I remember a flat where four Chinese restaurant workers were living. One of them was found dead in the morning," he added.

"The flat looked as though a bomb had gone off. The furniture was over turned, clothes and belongings scattered everywhere.

"A real mess. I thought that a fight had taken place and the dead guy was the victim.

"Turned out after post mortem and forensic examination he had died of 'natural causes' and so it was declared NO CRIME by the boss men. I still don't believe that. Must have been no overtime available."

But one of his most shocking moments involved almost being shot by his own boss. 

"I once found out that a bullet had missed me by about 12 inches and it was fired by my boss. Thankfully he wasn't a great shot," the retired detective said.

And there were quite a few things he was forced to do to remain undercover. 

He said: "I've been a drug user and dealer. A drug importer, a drug supplier, and was on the fringes of a growing operation.

"I've abducted people, held prisoners, took part in an armed robbery, committed numerous acts of aggression as part of a mob, lots of assaults but ever only in self-defence.

"Carried illegal firearms and other weapons. Visited houses and places of disrepute.

"The list just goes on. When you're undercover you just become part of what's going down, or you wouldn't last long."

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But luckily his life has settled down quite a bit since retiring. 

He revealed: "I still live in Glasgow, but now see it through the eyes of an old man, who just wants to be with his grandchildren in the park, go on nice holidays and fall asleep in front of the TV at night.

"The adrenalin has long since stopped pumping and I have no desire to be involved in anything more strenuous than walking football or a wee cycle."

You can pre-order his book HERE.