Superficially the post-war Kirk was in better shape than it had been for 200 years. The return of the Seceders and the Free Church meant that the Kirk could now claim a third of adult Scots as members, which made it more of a national church than its much larger English counterpart. Fewer than half of England's Christians supported the Church of England: the Kirk could claim two-thirds of all Scottish church members. The Beveridge report of 1942 had laid the foundations for a modern welfare state which would protect its citizens from cradle to grave and that faith in government ability to produce a better world gave the Labour party its victory in 1945. The immediate postwar period was a time of confidence in institutions and social planning that allowed the national church to claim a renewed salience. The churches also benefited from a very strong desire among the demobilised service men and women and their families to return to normal.

But there were troubling under-currents. For all the desire to return to normal, the war had changed many people. It is difficult to exaggerate the extent to which settlements and settled patterns of behaviour were disrupted by six years of a war which, one way or another, mobilised most of the population. In total, around 600,000 Scots men were involved in the armed forces, the vast majority of them being moved from their home cities, towns and villages and pressed into the company of comrades from very different social and religious backgrounds.

An account of religion in modern Scotland could start anywhere but this will begin with Scotland's maritime fringes for three reasons. The first is trivial: in their very different ways Lewis, Orkney and Shetland are breathtakingly beautiful. The second is relevant: too often Scotland is reduced to Glasgow and its religious culture is reduced to sectarian conflict. The third is important: it is easier to see social processes at work in small and clearly defined areas. In 1900 the peoples of Lewis, Orkney and Shetland were similarly likely to be churchgoing. By 2000, the people of Lewis were almost three times as likely as those of the Northern Isles to attend church. And, as we will see, that divergence came before the oil industry changed Orkney and Shetland. So we have something to explain.

We also have a good chance of explaining it. The value of Lewis, Orkney and Shetland for systematic comparison is that in 1900 the three islands were similar in many respects. They were part of the same state, had the same national church and were subject to the same system of law and public administration. They were economically similar: their peoples eked out mostly thin livings in combinations of subsistence farming and fishing that were protected by the Crofters Act of 1886. There were differences in weighting – the people of Lewis and of Orkney were crofters with boats while the typical Shetlander was a fisherman with a croft – but they were more like each other than any was like the people of the lowlands.

In February 2013 Cardinal Keith O'Brien resigned. Three priests and one former priest had accused him of ‘inappropriate behaviour’ in the 1980s. Although he initially denied the charges, the Vatican pushed him to quit a few months before his due retirement at seventy-five. In some ways O'Brien was progressive. He was in favour of priests being allowed to marry. When Steve Gilhooley published his account of having been abused at a seminary in Cumbria, O'Brien defended him against Vatican officials who seemed more concerned about Gilhooley than about what he revealed. But O'Brien had also been such a vocal opponent of gay marriage that in 2012 the gay rights campaigning organisation Stonewall had made him its Bigot of the Year.

Two of O'Brien's colleagues could have made Stonewall's short list. Philip Tartaglia, Archbishop-elect of Glasgow, told a conference on religious freedom at Oxford University:

As of the autumn of 2013 only the most basic data on religious identity from the 2011 census are available and it is not yet possible to explore the correlations (for example, place of birth and religion) that would help explain changes since 2001. The 2011 census asked only for current religious identity. Dropping the ‘religion of upbringing’ question means that some reasons for changes are obscured. It also means that even when all the data is released we will not be able to address questions (such as the links between religion and social mobility) where how people were raised may be more important than what they became possibly half a century later. A further problem is that a small but vital part of the 2001 data – the ‘Other religion’ and ‘No religion’ categories – has been recoded so that some responses which were then coded as ‘Other religion’ have now been shifted to the ‘No religion’ set. A final reason for not replacing the 2001 figures in the text with those for 2011 is that the 2001 census coincided with an edition of the national Scottish Social Attitudes Survey and a large survey of Glasgow, both of which were concerned primarily with religion and supposed associated characteristics. The three sources together allow for considerable depth of analysis and adding the 2011 census figures would have made parts of them even more complex than they are now.

On the afternoon of 30 June 2007, a dark green Jeep Cherokee was driven into the front of the terminal building at Glasgow airport. Security bollards stopped the car breaking through the doors. There was a series of small explosions but the blasts and the subsequent fire were contained within the Jeep. Five members of the public were slightly injured, some hurt tackling the terrorists. Police identified the two men apprehended at the scene as Bilal Abdullah, a British-born doctor of Iraqi descent working at the Royal Alexandra Hospital in Paisley, and Kafeel Ahmed, also known as Khalid Ahmed, a Cambridge student. It was quickly established that the two men had been responsible for a failed bomb attack on London's West End a few days earlier. Ahmed died of his burns. Abdullah was sentenced to thirty-two years in prison.

The initial reaction to the airport attack was shock at what Scots took to be the latest atrocity in a sequence that started with the Twin Towers in 2001 and included the 2005 London tube bombings. But once it became clear that the sole fatality was one of the terrorists, the tone changed quite noticeably. John Smeaton, a baggage handler who weighed into the fight between a policeman and one of the terrorists, became a celebrity, not just for his prompt action in joining the fray and pulling clear an injured civilian, but also for his curt description of his actions: ‘So I ran straight towards the guy, we're all trying to get a kick in at him, take a boot to subdue the guy’.