Patrick Simpson, in line with the evangelical commitment of the Scottish Free Church,[3] had opted for missionary work in the newly settled colony,[4] arriving in Australia in 1858.

It was a time of transformation in the Scottish religious, intellectual, and social order due to the renewal triggered by the Disruption, innovations in scientific thinking, and rapid industrialisation.

He was most notably involved in the negotiations arising from the Lambeth Conference,[22] the Prayer Book Controversy, and the setting up of the Federal Council of the Evangelical Free Churches[23] to foster cooperation between the nonconformist denominations.

This was due to the discord, and at times vehement friction,[26] between the majority, under the leadership of Principal Rainy who championed the movement for union with the United Presbyterian Church,[27] and a small dissenting minority[28] – later to become known as the "Wee Free Kirk".

The minority, who were essentially from the Highlands and Western Isles,[29] disapproved of the more liberal and evangelical interpretation of the Westminster Confession of Faith and claimed to be the sole authentic representatives of the Free Church.

He was immediately drawn into the debate in support of Rainy[34] and, according to an editorial in the Journal of Presbyterian Historical Society of England, it was this experience that served as his apprenticeship in ecclesiastical affairs and as a negotiator.

[36] He became the youngest member to the Assembly's "Advisory Committee" which had been set up by Rainy to manage the situation[36] and was called on to address meetings across Scotland[37] and in London, to write pamphlets and articles for the press, and to negotiate with landlords to obtain land for temporary places of worship.

During the war period, teaching at Westminster was suspended[10] and Carnegie Simpson carried out chaplaincy for the 1st Eastern General Hospital and was in charge of the congregation at St John's Wood, London.

[44] It is not so much as a scholar that Carnegie Simpson is remembered but rather as a forceful teacher,[45] less concerned with detailed historical analysis than in providing his students with a broad framework of the underlying essentials.

[46] According to Hay Colligan, Carnegie Simpson's professorship at Westminster was essentially characterised by a widening of the scope of the subject beyond the strict realms of Presbyterianism to a more global, historical view of "the general development of doctrine, dogma and polity.

"[47] Despite his pre-war declared lack of enthusiasm for ecclesiastical affairs, Carnegie Simpson soon found himself drawn back into the world of Church politics and committee work.

In the words of Professor Healey, it was what Carnegie Simpson did "beyond the strict bounds of the English Presbyterian Church, but in the realm of inter-Church relations that his impact was most significant.

[59] In order to better meet the needs of the new century and because of growing incoherence and disparity in the use of the liturgical rites in the Church of England, a reformulation of the Prayer Book had become increasingly pressing.

There was fear of the current increasing ritualism,[62] that the Reformation Settlement might be imperilled,[63][64] while more extreme opinions evoked the danger of a return to "all the errors and horrors of Roman Catholicism".

[65] On 17 September 1927, Carnegie Simpson wrote a memorandum to the Ecclesiastical Committee[66] pointing to the shortcomings and ambiguities of the text and the need for the Free Churches to obtain strong guarantees before approving it.

[72] Carnegie Simpson served as an intermediary between Sir William and Lady Noble and Westminster College with regard to the donation of the Memorial Chapel in commemoration of their son, killed on the Belgian front in 1915.

[76] The book, an apologetics in answer to the "rising assault of agnosticism",[77] was based on a series of lectures given at evening classes in his early years at Renfield and aimed at "the honest doubter".

[82] Amongst other things, the book discusses in length Rainy's role in the notorious heresy trial brought against Professor William Robertson Smith and the legal crisis triggered by the House of Lords ruling in 1904 against the Scottish Free Church.

[88] It is written in the light of his experiences with Rainy during the Scottish Church Crisis and, as the dedication to Archbishop Davidson implies, the Lambeth conversations and the Prayer Book controversy.

Recollections – Mainly Ecclesiastical but Sometimes Human (1943): As its name suggests, this, his last book, is essentially autobiographical, except for the epilogue in which Carnegie Simpson returns to reflect on certain fundamental issues of life.

Although the book's literary merits seem doubtful,[95] Carnegie Simpson is sufficiently attached to it to afford it several lines in Recollections, even if his remarks are made with his characteristic, wry humour.

In a letter addressed to The Times in 1907, Carnegie Simpson appealed to readers to allow him access to personal documents to assist him in the writing of the biography of Principal Rainy.

[105] Likewise, for Carnegie Simpson, over and above an account of the career of the eminent churchman, the talented negotiator and the successful author, it is necessary to make some attempt to portray the "inner man".

[110][111] Intimately linked to his public charisma are two other traits, namely his fairness in dealing with opposing opinions in debate,[112] and his abiding sense of humour which played no small part in his success as a negotiator.

[116] One of his favourite maxims, which hung framed above his desk, was: This may go some way to explaining why his wit is, at times, readily employed to point to any signs of pretension or self-inflation[118] and, if required, could be scathingly caustic.

At the same time, however, Carnegie Simpson was, according to Professor Healy, "a profoundly religious man"[130] as is reflected in his writings by his preoccupation with the eternal questions of the suffering of the innocent,[131] of social injustice[132] and of despair.

[137] While it is certain that Carnegie Simpson relished in the "Comédie humaine",[138] enjoying, as Healey nicely puts it, the company of men and women of all sorts, "whether in Episcopal palaces or in public houses",[139] the other side of the coin is that the arresting style and the high-profile stances that he adopted could not receive universal approval.

Others complained that his search for compromise with the Anglicans and Church unity did not reflect the opinion of the Presbyterian rank and file,[140] and the obvious pleasure with which Carnegie Simpson narrates his encounters with the "Kalos k'agathos"[141] (The beautiful and the good) and otherworldly acquaintances was not always to everyone's taste; to some, such manifest urbanity was not quite appropriate.

"[143] Lumsden[144] and the "Dictionary of Scottish Church History & Theology"[145] regret a tendency towards hagiography in his most highly considered book, "The Life of Principal Rainy."

[146] Equally, on occasions Carnegie Simpson voiced opinions on ethical and political questions[147] or indulged in sweeping generalisations[148] which, with the advantage of hindsight, we may today consider with askance.