Born: September 3, 1945;

Died: February 19 2018

SIR John Orr, who has died aged 72, was Chief Constable of Strathclyde Police, at that time the country’s biggest force, from 1996 until 2001; previously, as joint head of Strathclyde’s CID in the rank of Detective Chief Superintendent, he had been the lead officer in the investigation of the Lockerbie bombing.

He had other notable roles – he was chairman of Kilmarnock FC from 2001 to 2003, and then the club’s honorary president; and he chaired a commission which produced a 300-page report into marches and parades – but he will inevitably be remembered chiefly for his part in co-ordinating what was the single biggest murder investigation in the history of Scottish policing.

The Lockerbie air disaster, on December 21 1988, was not only a huge murder inquiry, but one of the most serious acts of terrorism in the West. Pan Am Flight 103, which had originated in Frankfurt, had then left London bound for New York and ultimately Detroit, when it was torn apart by a bomb over the Borders town. All 243 passengers and 16 crew were killed, as were 11 people on the ground; several houses in the town’s Sherwood Crescent were destroyed.

Orr, who had been the joint head of Strathclyde CID, was brought in to lead the early stages of the investigation. “There is an awful lot of hard work that will have to be done in the course of the next weeks and months,” he told the New York Times.

That was a characteristic piece of understatement. The magnitude of the civil and criminal investigations was almost unprecedented: some 4 million items of wreckage were spread over 2,000 square kilometres; more than 10,000 of them were retrieved and tagged as evidence.

Around a thousand police officers and soldiers were employed in the search, with the instruction: “If it isn’t growing and it isn’t a rock, pick it up.” Some 15,000 witness statements were taken by Dumfries and Galloway Police (Scotland’s smallest force) and the FBI, which assisted in the investigation.

Orr directed the opening stages of the operation, which eventually led to enquiries throughout Europe, focusing particularly on Malta, and to the conviction of Abdelbaset al-Megrahi in January 2001. In 1990, Orr was appointed deputy chief of Dumfries and Galloway Police.

John Orr was born on September 3 1945 in Kilmarnock, the son of Samuel Orr and his wife Margaret (née Walker) and educated at James Hamilton Academy in the town. On leaving school at 16, he became a cadet in Renfrew and Bute Police, before returning home to Kilmarnock Burgh Police from 1964-66. He then had a three-year stint south of the border, with Cumbria Constabulary, and from 1969 until 1975 served in Ayrshire.

In 1975 he joined Strathclyde Police, where he served until his secondment to the Lockerbie investigation, rising through the ranks to become Detective Superintendent in 1984 and in 1987 Detective Chief Superintendent and joint head of CID. He also acquired additional academic qualifications, with a BA from the Open University in 1983, and later a diploma in forensic medicine from Glasgow University.

He was Deputy Chief Constable for Dumfries and Galloway from 1990-94, and appointed OBE in 1992. He then spent a year as the Assistant Inspector of Constabulary for Scotland before taking up his role in charge of Strathclyde. In 1997 he was awarded the Queen’s Police medal and in 1997/8 was president of the Association of Chief Police Officers in Scotland.

Orr was a lifelong fan of Kilmarnock Football Club and in retirement served as the club’s chairman between 2001 and 2003, and was thereafter honorary president. His other hobbies included reading and hillwalking. His experience in the Lockerbie investigation led to his becoming a regular speaker at conferences on security and terrorism internationally.

In 2004, he was asked to conduct a review into marches and parades; he delivered a 300-page report to the Scottish government the following year. Orr interviewed around 125 witnesses and travelled to Northern Ireland to learn from their experiences. His conclusions centred on extending the notice period, broadening community involvement and ensuring that one individual or organisation should be identified as responsible for the parade, and held liable for behaviour during it.

It was a mark of Orr’s tact and common sense that his conclusions – on what had been considered a highly contentious issue – were broadly welcomed by both the Grand Orange Lodge and Cairde Na hEireann. The Scottish government accepted his findings in their entirety.

Sir John Orr died on February 19 2018. He married, in 1966, Joan Underwood, with whom he had two sons and a daughter.