THE Irish heritage of many Scots lies behind a trend that will see Catholicism become the most popular religion in the country by 2024, pre-eminent historian Sir Tom Devine has said.

The renowned academic explained that the Catholic Church in Scotland has seen congregations drop at a slower rate than their counterparts at the Church of Scotland because of a "social identity" connected to Irish migrants.

Figures from the Scottish Household Survey suggest that the number of Scottish Catholics have remained relatively stable over the last decade while the Kirk has seen the number of worshippers trickle away.

The findings, reported in the Scottish Catholic Observer, showed 14 per cent of Scots identify as Catholic – a decrease from 15 per cent in 2009.

However those who claim affiliations to the Church of Scotland have declined by ten per cent to 24 per cent in eight years.

There has also been a corresponding rise in the number of people claiming to b have no religion, which now stands at more than half.

Sir Tom – himself a Catholic – said of the religious trend: "Ever since the mass migration of the Irish into Scotland in the 19th and then the 20th centuries, Catholicism has always had if you like a social identity role as well as a spiritual function and that might be a factor which reduces the rate (of decline).

“There is a phenomenon known as cultural Catholicism with people who might be slightly more agnostic than the faithful who adhere to the faith because it is part of their social and cultural identity, and I don’t think that factor is relevant to membership of the Church of Scotland.”

And he added: "Since church-going went into decline in about the 1960s, the rate of decline in the Catholic Church has been slower over the period since then to the present day.

"That is not to say there has not been haemorrhage. There has, obviously."

Sr Tom, who is the Sir William Fraser Professor Emeritus of Scottish History and Palaeography in the University of Edinburgh, said the Church of Scotland was a pillar of the Scottish establishment for hundreds of years.

"In the eighteenth, nineteenth and then twentieth century the Church of Scotland had a much wider role than simple spirituality," he said.

"It was responsible up until 1872 for education, it was responsible for the poor law and obviously providing the moral value of society.

"So the decline in the Church of Scotland is an enormous and historic sea change in the nature of Scottish society."

Sir Tom said that, as the influence of the country's traditional religions begins to wane, questions will arise over the future of Catholic education and the direction of a post-Christian society.

He said: "The issue is going to be in the future – and this refers to both (denominations) – if this decline continues and we are dealing with a post-Christian society in Scotland, will the values which, leaving aside any issue of belief, have fashioned western civilisation not least Scotland for well over a thousand years, will they continue to prevail?"

Addressing the Scottish Household Survey figures, Rev Norman Smith, Convener of the Church of Scotland’s Mission and Discipleship council said: "With considerable numbers of people continuing to identify with both the Church of Scotland and the Roman Catholic Church this shows that the Christian faith continues to play a significant role in the life of our nation.”