It was Tony Blair’s spokesman, Alistair Campbell, who said of New Labour, “We don’t do God” and “God was a disaster area” for the party. That may have been wishful thinking on Mr Campbell’s part, as his boss most certainly did “do God”. Mr Blair recognised however, playing the religious card in politics risked, “people thinking you are a nutter”. In recent times Mr Blair has subtly changed his position, placing greater emphasis on faith than on God. In a recent magazine article, he argues faith is on the ascendency around the world, even on stony ground like China.

His successor as PM, Gordon Brown, regretted in his memoir, My Life, Our Times, that he hadn’t been more open about how his religious convictions shaped his political beliefs and actions. If so, he might have been more forthright in calling for ethical banking practices, particularly during the financial crises of 2008 and 2009. The eviction of the moneylenders from the temple surely would have offered suitable inspiration. In his 2011 lecture on Faith in Politics, Mr Brown described how in the 1930s, Stanley Baldwin would regularly invoke “AG” (Almighty God) in his speeches.

Yet, there is a contradiction here. On the surface at least, there is strong evidence that Scotland is becoming more secular. The 2011 census suggested that those professing no religion (37 per cent), had become the country’s largest “religious grouping”. In my home city of Aberdeen, the figure was 48%. In the five years to 2017, Church of Scotland membership declined by around 20%. In his memoir, Mr Brown regrets what he perceives to be the growing “detached indifference” towards religion. Set against that background, one would expect a corresponding decline in the relevance and influence of religion on the nation’s political life.

In his recent book, The Impossible Office? The History of the British Prime Minister, Anthony Seldon examines the influence of religion and faith on the occupants of Number 10. He concludes, “The death of religion has been much exaggerated”. While recognising the declining role of religion in British politics over the past 300 years, Seldon argues that it still restrains and influences political leaders including prime ministers and, in the Scottish context, first ministers. Indeed, the growth of multiculturalism in Scotland and the UK in general means politicians have to take serious account of how policies will play out amongst diverse faith groups. The electoral success of the SNP in recent years has involved the “capture” of the Catholic and Muslim vote. In a Spectator article in 2016, James Macmillan wrote that the links between the Scottish Catholic church and the SNP had been “obvious for a while”.

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In the main, recent prime ministers have kept their faith at a healthy distance from their politics, considering their religious beliefs to be a private matter. David Cameron was able to joke that his faith was a bit like the radio signal in the Cotswolds, “it comes and goes”. Nevertheless, he wasn’t above playing the religious card when it suited him. When drumming up support for his ill-fated Big Society initiative in 2014 he declared, “Jesus invented the Big Society 2000 years ago”.

To varying degrees, prime ministers’ personal convictions have been enlisted to underpin and justify their political vision of an improved or, in Margaret Thatcher’s case, a different society. Mrs Thatcher’s religious rhetoric set teeth on edge from the moment she set foot in Downing Street in 1979, quoting St Francis Assisi; “Where there is discord, may we bring harmony”. Aye, right. Her divisive and destructive economic policies were dressed in pseudo religious claptrap, writing in her memoirs that there was, “A deep and providential harmony between the kind of political economy I favour and the insights of Christianity”. In her infamous 1988 “Sermon on the Mound”, Mrs Thatcher suggested the Good Samaritan was able to help the unfortunate traveller only because he was rich.

The British public has a healthy suspicion of politicians in general and, in particular, those that flaunt their religious beliefs. Things are different in other parts of the world. In the US, presidents deal with a more fundamental and evangelical electorate and are expected to do what FD Roosevelt called the “God stuff”. It’s difficult to imagine a British prime minister repeating ex-President Trump’s stunt of being photographed outside a Washington church brandishing the Bible as a prop. Yet, the rise of aggressive religious fundamentalism in the US and in many other places poses a serious threat to secular politics and consequent rights and liberties.

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As Anthony Seldon points out, UK politicians still have to take account of religious opinion. The religious constituency cannot be ignored, particularly by the Conservative Party. Research on voting patterns in the 2014 General Election for example, suggested a strong link between being Anglican and voting Conservative. A greater proportion of Conservative voters considered themselves to be religious. No-one’s arguing that it’s inappropriate for religiously minded politicians to draw on their beliefs and values when shaping the policies that they put to the electorate. Additionally, religious opinion has a role to play in holding politicians to account. Mrs Thatcher had little time for “wet bishops” who were critical of her economic and social policies. More recently, a number of church leaders have spoken out about aspects of Brexit, climate change and cuts to overseas aid.

Religion has a legitimate place and role in all aspects of national life, including politics. Nevertheless, that place and role is to act as a guide to ethical conduct and provide a yardstick against which policy and practice can be judged. The real danger, as we have seen around the world, is the intertwining of evangelical and aggressive religion with the political process.

Our columns are a platform for writers to express their opinions. They do not necessarily represent the views of The Herald.