Daniel Coughlan is a teacher in West Sussex.

In England the month of May, with its Morris dancing, is a time when people risk looking nuts. Thirty years ago today Margaret Thatcher was north of the border doing the very same. Not dancing with sticks but something even more disturbing: she was ‘doing God’ in public, and with bells on.

In what became known as the ‘Sermon on the Mound’, her address to the General Assembly of the Church of Scotland, Thatcher explicitly spelt out her Judaeo-Christian worldview. She stands out in modern British politics in how she consistently and publicly witnessed to a firm faith in God.

All Prime Ministers since Macmillan have professed a personal belief in God. Yet one of the most devout, Tony Blair, confessed in 2007 – the year he left Downing Street – to keeping his faith quiet. He explained, “you talk about it [faith] in our system and, frankly, people do think you’re a nutter”. This is a sad indictment of the British political scene.

Politicians are still permitted to have had a religious upbringing, and even to maintain religious customs. Theresa May could happily launch her Conservative leadership bid as the vicar’s daughter, and as Prime Minster reveal that she was giving up crisps for Lent. But many voters seem uncomfortable with a politician drawing upon a belief in God.

Yet all belief systems have a ‘God’ in that they demand some ultimate rationale or have some final concern: it might be the sovereignty of pleasure and pain, or economic equality, rather than a loving creator who invites our friendship. In a democracy the latter idea should not receive any special treatment. It can compete – like all ideas – on its merits. But it should not be silenced.

The silencing of faith in public life reflects a range of anti-religious prejudices: faith as inherently unreasonable, antithetical to freedom, socially divisive, or unconcerned with material prosperity. Thatcher’s example challenges such stereotypes.

In 1988 Thatcher unashamedly spoke of things theological. She referred to “Our Lord Jesus Christ, the Son of God” who “chose to lay down His life that our sins may be forgiven”, and how “if we open our hearts to God, He has promised to work within us.” She confidently presented her faith as “true” but she did not ask anyone to take her word for it.

Later that same year, David Frost quizzed Thatcher in some depth, asking “do you believe there is a God or do you know there is a God?” She retorted, “Believing there is a God is knowing there is a God”. She appealed to matters such as the existence of conscience and the notion of fundamental human rights to support her surety. She even sought to account for the problem of evil and suffering.

Thatcher was no theologian but she was theologically engaged and engaging. She spoke of her favourite biblical texts – psalms 139 and 46 – and interpreted their central message for political life, “that each and every person matters”. Frost hailed her comments as “wonderful” and “superb”. He was no Paxman, but then again Thatcher was no Blair. She was willing and able to argue for her foundational belief.

Thatcher had spoken about her faith for years. In 1987, she told John Humphrys on Today, “The fundamental reason of being on this earth is so to improve your character that you are fit for the next world.” Before becoming Prime Minister, in a 1978 speech at St Lawrence Jewry, she had related this same theme to public policy: “politics is about… establishing the conditions in which men and women can best use their fleeting lives in this world to prepare themselves for the next.”

Few believing politicians, let alone aspiring Prime Ministers, would speak thus today. But the difference is explained not just by our antagonistic times, but that Thatcher had confidence in her religious beliefs: that they were not only well-founded, but, being so, they could positively contribute to political life.

Central to Thatcher’s Christian faith, as expressed to the General Assembly, was that man was “endowed by God with the fundamental right to choose”. As she explained in 1978, “my own faith in freedom does not rest in the last resort on utilitarian arguments”. Her drive towards a free and responsible society – with all the social and economic fruits it promised – had theological roots.

Thatcher’s faith also motivated her deep – and often wilfully overlooked – commitment to social justice. In 1978, she recalled the Pauline notion of the Body of Christ and commented, “From this we learn our interdependence, and the great truth that we do not achieve happiness or salvation in isolation from each other but as members of Society”. In Scotland she recalled the government’s concern to “have laws to provide for health and education, pensions for the elderly, succour for the sick and disabled”.

Thatcher’s faith was far from religiously or culturally divisive. She reflected that “one of the great principles of our Judaic-Christian inheritance is tolerance” and explained that there was “absolutely nothing incompatible between…our desire to maintain the essence of our own identity” and “equality under the law, of proper respect and of open friendship”. Other religious faiths of today might be different, but they – like atheistic totalitarian projects before them – will struggle to compete in our democracy.

Rather than being down on material wealth Thatcher professed how, “abundance rather than poverty has a legitimacy which derives from the very nature of Creation.” She reminded the General Assembly that it was not the creation of wealth that was wrong but “love of money for its own sake”. Material wealth, like social harmony and freedom, were not in any danger from Thatcher’s faith-filled politics. They were secured by it.

The modern-day closeting of politicians with religious faith not only reflects a range of anti-religious prejudices but it risks impoverishing public life. Thatcher’s public engagement with theology serves as a challenge both to those who unfairly dismiss religious faith, and those politicians of faith that acquiesce to such prejudice. The exclusion of religion from public discourse risks losing its important public benefit.

In 1978, writing in the Daily Telegraph, Thatcher warned those who shared her politics about abandoning Britain’s faith heritage. She observed:

‘there are loyal supporters of the Conservative cause today who would describe themselves as agnostic humanists. To my mind, such people are living recklessly on the dwindling spiritual capital of our Christian culture. I do not believe that even the free and ordered society which as a party we are trying to foster can satisfy the deepest human needs, for this is beyond the scope of politics. I do not think that even this society will be able to sustain itself unless it keeps its religious foundations in good repair.’

If Thatcher’s prophecy proves right, if the political fruits of the Christian faith wither without nurturing their theological roots, future generations might well wonder at our modern disdain for faith in politics. If religious faith is not given space in our public discourse, in another 30 years, it is we that might look extremely foolish.