Slightly more than one-third (38 per cent) of the 3,879 people polled for the British Social Attitudes report described themselves as Christian, down from half (50 per cent) in 2008 and nearly two-thirds (66 per cent) in 1983.
Conversely, those identifying as Muslim increased exponentially, up from 1 per cent in 1983, rising to 3 per cent in 2008 and 6 per cent last year.
The findings represent the first time the percentage of those describing themselves as Christian dropped below 40 per cent since the survey began in 1983, although those identifying as no denomination Christian increased from 3 per cent in 1983 to 13 per cent in 2018.
A Church of Scotland spokesman said: “It’s a time of challenge, but it’s also a time of opportunity.
“Whether we are many or we are few, our calling remains the same, to love God and to love our neighbour, and this is why the Church of Scotland will always seek to be a force for good in society.
“Irrespective of the Church’s popularity, you still find Christians active at all levels of society seeking to live out the generous love of God.”
More than half of all people polled (52 per cent) said they do not belong to any religion, up from nearly one in three (31 per cent) in 1983.
The report by the National Centre for Social Research published today said: “The past two decades have seen international conflict involving religion and domestic religious organisations, putting themselves at odds with mainstream values.
“We find a dramatic decline in identification with Christian denominations, particularly the Church of England, a substantial increase in atheism and in self-description as ‘very’ or ‘extremely’ non-religious ... but tolerance of religious difference.”
The data shows 11 per cent of those with a faith attended a religious service at least once a week – a rate that has remained stable since 1998.
Half (50 per cent) of those polled said they never pray, up from 41 per cent in 2008 and 30 per cent in 1998, although those who pray “several times a day” is up from 5 per cent two decades ago to 8 per cent last year.
Almost two-thirds (63 per cent) of Britons polled agreed that religions bring more conflict than peace, while 13 per cent disagreed.
The data also showed 51 per cent of those polled “feel positive” towards Christians, compared with 30 per cent for Muslims.
Similarly, 4 per cent of people have negative thoughts about Christians – level with Buddhists – compared with 17 per cent for Muslims.
Responding to the findings, Andrew Copson, chief executive of non-religion charity Humanists UK, said: “For the third year in a row, the British Social Attitudes survey – the gold standard in reliable data on our society – has shown a majority of Brits are non-religious.
“With these trends set to continue, policy-makers in every field, from education to constitutional law, to health and social care need to wake up to such dramatic social changes, particularly the rise of the non-religious and the decline of Christianity.”