Mr Sinclair joined the commission in 2003 and will have served for over 18 years when he retires, which the commission believes makes him the longest serving chief executive of such an arm’s length body in the public sector in Scotland.

Solicitor Aamer Anwar described Mr Sinclair as an “outstanding” chief executive “who has never shied away from doing the right thing” and said it had been a “privilege” to work with him.

He told Scottish Legal News: “The Megrahi (Lockerbie) referral will probably be the biggest appeal that the UK will ever see and the conduct and quality of work in that case made the SCCRC a world-leading model that any jurisdiction could be proud of. But it is also testimony to the team built by Gerry.

“Gerry has been the architect of a modern SCCRC, which is usually the last hope for those who are the victims of a miscarriage of justice, his leadership has contributed immensely in fighting to give ‘hope’ when our justice system fails so badly.

“I for one will be sorry to see him retire, it has been a privilege to work with him and I wish him all the best.”

Bill Matthews, chairman of the commission said: “I am the third chair of the SCCRC to have had the privilege of working with Gerry, and I know that all current and former members of the commission will be very sad to see him leave. He has dedicated nearly two decades to leading the work of the commission in its examination of many hundreds of cases, and has become a respected ambassador for our work in countries as far afield as Canada, Norway and New Zealand.

“Throughout this period he has shown exceptional skill, diligence, sensitivity and fairness in his advice to the commission whilst providing exceptional leadership to the staff of the organisation. We are hugely grateful for his public service and appreciative of the early notice he has given us, allowing us to begin the challenging search for a replacement early.”

Mr Sinclair said: “It has been a great privilege to serve as the chief executive of such an important part of the criminal justice system during its first two decades. I joined the commission just a few months before it received the first application for review from Mr Megrahi, who was convicted of the Lockerbie Bombing, so it seems appropriate that I will be retiring from the commission on my 60th birthday just a matter of months after the High Court finally decided the appeal in this long outstanding matter.

“It is, however, only one of over 2,800 cases investigated, considered and decided during my time, by a wide range of highly diligent, talented and experienced staff and members of the board. It’s a testament to their dedication that, having originally intended to stay for only a handful of years I have remained here until my upcoming retiral.”