ON his first day as a detective, the body of 16-year-old Elaine Doyle was discovered on a street in Greenock.

And Strathclyde Chief Constable Campbell Corrigan, who worked for three years in Greenock's CID unit, has admitted he felt relieved to see a potential breakthrough days before he retires.

Police last week arrested a man in connection with the murder, which took place on June 1, 1986.He appeared in Greenock Sheriff Court on Monday and made no plea before being remanded in custody.

Mr Corrigan, 48, a father-of-three, said he felt "such pride" in the development because the force has never given up.

He said: "I was a new acting DC, it was my first murder investigation and I was just 22.

"To arrest someone the week before I retired was such an achievement. I felt such pride.

"We have never stopped. We were always wondering if we have done enough."

It is a poignant end to a 29-year career that has seen him help net Scotland's biggest heroin haul – 207kgs, worth about £51million found at St George's Cross, Glasgow, in 1999 – as well as being the head of CID during the 2007 terror attack at Glasgow Airport, launching the force's Campaign Against Violence and even attending Harvard University in America.

But after midnight on Sunday the force that shaped him will no longer exist.

To celebrate his retirement Mr Corrigan yesterday took one last walk around the beat in Greenock where he started aged 19.

He says his whole career – and personal life – has been shaped by the town.

"My memories of Greenock are that it was a bustling place, loads of people and lots of things going on," he said.

"There was quite a lot of deprivation and a much higher population than there is now.

"It was tough, but for a young police officer it was the best place in the world to work."

Mr Corrigan, from Ayr, admits policing was "written in the stars" for him. His dad Harry was in the force until he retired as a divisional commander in 1985.

"I came from a big police family," recalled Mr Corrigan. "As a child my dad would tell me about cases and places he had been and baddies he had arrested.

"I was always interested in the investigation side of things.

"But when I joined I didn't have a plan."

His wife Carol, who is a former police officer, is from Greenock and used to work in a local chippie while he was a cop there.

"I used to go to Ronnie's chip shop all the time when I was young," he said.

"The whole family goes there now, so my kids love the chips as much as we did when we were kids."

Carol, who worked in Govan police office, left the force and became a full-time mum to Grace, now 16, Finn, now 15 and Maire, now 13.

Mr Corrigan was promoted to Detective Sergeant in Govan, before heading to Pollok to join the crime squad.

He said: "I worked all over the world, in The Hague, all sorts of places. My team did the biggest ever seizure of heroin in Scotland in Glasgow. We formed the first counter corruption unit in 2002, which was really interesting."

He says being promoted to DCI at Govan was a significant moment in his career.

"That was a mega job. It is iconic because it's the biggest, maddest place in the world.

"We oversaw the investigation of Jamie Stevenson, a known Glasgow criminal. It really changed the way we do our business."

The team also led the investigation into Raymond Anderson and James McDonald, who received 35 years – the longest sentences ever passed by a Scottish court – for shooting dead Michael Lyons, 21, on December 6, 2006 and trying to murder two other men in Glasgow.

Mr Corrigan, a self-confessed workaholic, also rushed back from a family caravan holiday in Tuscany after he heard about the terrorism threat to Glasgow in June 2007.

"I came back to work the day the attack happened at Glasgow Airport," he said. "I didn't go home for days while we worked on it."

He also cites dealing with the inquiry into parcel bombs being sent to Celtic manager Neil Lennon and other high-profile people as major moments.

He added: "I was the person who went with (former Strathclyde Chief Constable) Steve House to the football summit.

"We had to let the public know the money that was being spent on the consequences of football, through domestic violence, policing and everything else. It has to be addressed."

Aside from the policing, Mr Corrigan went to Harvard University to study a course.

"I sat in the auditorium in the same place Nelson Mandela and Bill Clinton did their speeches."

He also wrote a paper on why Scotland should move to a single police force, sparking the debate.

When he hangs up his police hat he plans to emigrate to Canada this summer with his family.

"My family have done so much for me that it is time I supported them," he said. But policing may still be part of his life.

"I think my youngest daughter might join the police," he said. "She has that inquisitive, curious part of her that I had.

"She is a chancer and could talk her way out of anything ... that is what I have been able to do."