The Rev Dr Marjory MacLean, the Depute Clerk of the Church of Scotland's General Assembly, will offer her own insight into the at-times "brutal" history of Church-state relations.

Dr MacLean, a former solicitor, will examine the difficult legal questions posed for the national Church in Scotland since the Reformation, including most recently the European Employment Directive which has forced all churches to engage with government over questions of the legal position and rights of working ministers.

She will also demonstrate how hard it is to decide where to draw the line between the Church's own spiritual jurisdiction and the secular jurisdiction outside it.

She will offer an insight into the changing attitude of civil society to the legal role of the Church and will also highlight the disasters that have resulted from the abuse of God-given power.

Dr MacLean has been Depute Clerk of the General Assembly of the Church of Scotland since 1996, is a chaplain in the Royal Naval Reserve and is a lay member of St Andrews University Court.

"In today's world the Church has to resolve two profound questions together: how to regulate our affairs in ways that pass legal scrutiny, and when to insist that we march to the beat of a different, heavenly drum?" said MacLean.

"For 120 years Chalmers Lectures have asked those questions, each for his own age. This new series faces new challenges in the perennial puzzle."

The historic Chalmers Lectures were established by trust deed in the late 19th century in memory of Thomas Chalmers, the dominant figure of the Disruption, in order to consider questions of the governance of the Church, and the headship of Jesus Christ.

This year's Chalmers Lectures take place at King's College Aberdeen on Monday 8 October.