"Sermon on the Mound" is the name given by the Scottish press to an address made by British prime minister Margaret Thatcher to the General Assembly of the Church of Scotland on Saturday, 21 May 1988. This speech, which laid out the relationship between her religious and political thinking, proved highly controversial.

Thatcher has been described as Britain's most religious prime minister since William Ewart Gladstone. She was raised as a Methodist and had preached as such in her Oxford years, but later she became a member of the Church of England. She understood her political convictions in terms of her faith. However, as prime minister, she repeatedly found herself in conflict with the churches; she was reportedly "livid" when the Archbishop of Canterbury was critical of the Falklands War, and she saw the Church of England's Faith in the City report, with its theological criticism of her social policies, as an illegitimate intrusion of the church into the political sphere.

In Scotland, Thatcher was particularly unpopular, and in the 1987 general election, the Conservatives lost more than half of their seats north of the border. In May 1988, Thatcher chose Scotland as the setting for a televised speech before the Church of Scotland's General Assembly, which may have been co-authored by her chief policy advisor, Brian Griffiths, and which was intended in part as a response to Faith in the City. She was the first prime minister ever to address the body directly.

The assembly had convened for its first session of the year at 10 a.m. but paused its business to allow the timing of the Prime Minister's address to coincide with the television schedule. She appeared in a Tory-blue suit and hat. Even before she spoke, some in the church objected to her being given this platform because of the damage done to Scottish communities by the closure of coal mines and shipyards. After welcoming her to the assembly, the Moderator, James Whyte, professor of practical theology at St Andrews, asked, following the formal procedure, if it was the will of the assembly that the Prime Minister be permitted to speak. She had to wait while six parish ministers came forward to register their dissent.

The name "Sermon on the Mound" is a play on Jesus's Sermon on the Mount and the artificial hill in Edinburgh called the Mound, on which the church's Assembly Hall stands. It reflects the sermon-like tone of her address, which is normally discouraged in debates in the assembly. It has also been seen in the context that Thatcher was preaching to a church and nation that had mostly rejected her ideology. In an interview with Scotland on Sunday in October 1988, Thatcher said: "[I]t was not a sermon on the mount, it was Scotland asking me fully and frankly to give my beliefs, doing me the supreme courtesy and honour of asking me and listening with great attention."

In the address, Thatcher offered a theological justification for her ideas on capitalism and the market economy.

One key idea in Thatcher's political thinking was individualism, notably summed up in her 1987 statement that "[t]here is no such thing as society". This aligns with the theme of individual personal salvation in the evangelical Wesleyan tradition in which she was raised. A main theme of the speech is, therefore, the individual, both in the context of spirituality and of economic agency. Citing a view that "Christianity is about spiritual redemption, not social reform", she asserted that, while it would be wrong to see these as opposites, Christians should emphasise personal responsibility. Quoting from the hymn "I Vow to Thee, My Country" (which had never been part of the Scottish tradition of worship), she said: "It goes on to speak of 'another country I heard of long ago' whose King can't be seen and whose armies can't be counted, but 'soul by soul and silently her shining bounds increase'. Not group by group, or party by party, or even church by church—but soul by soul—and each one counts."

Choice played a significant part in Thatcherite reforms, and she claimed it as a Christian value by linking it with the idea that Christ chose to lay down his life and that all individuals have the God-given right to choose between good and evil. Thus theological ideas of free will flowed together in her thinking with free-market ideas of consumer choice.

The speech contains an ambivalence towards democracy. It points out that "nowhere in the Bible is the word democracy mentioned" and, ideally, when Christians meet, the purpose should not be "to ascertain what is the mind of the majority but what is the mind of the Holy Spirit – something which may be quite different". Nevertheless, she professes to be an enthusiast for democracy because, more than any other system, it safeguards the value of the individual and restrains the abuse of power: "[A]nd that is a Christian concept." Thus democracy is linked in her thinking to individualism rather than to the community.

A central pillar of Thatcherite economics was the role of private enterprise in producing wealth. In the speech to the assembly, she linked this to biblical commands: "We are told we must work and use our talents to create wealth. 'If a man will not work he shall not eat' wrote St. Paul to the Thessalonians. Indeed, abundance rather than poverty has a legitimacy which derives from the very nature of Creation." However, she did not mention the Good Samaritan; her remark that the Samaritan could not have helped if he had not been rich and that the parable teaches us first to create wealth and then help the poor, has sometimes been cited in the context of this speech, but was made elsewhere. It has been suggested that by 1988 the Samaritan interpretation had become "an albatross" which she avoided repeating.

When Thatcher finished speaking, the Moderator, James Whyte, formally presented her with church reports on homelessness, poverty and social security, which was interpreted in the press as a polite rebuke. One of these, entitled Just Sharing: a Christian Approach to the Distribution of Wealth, Income and Benefits, advocated heavy taxation on the rich and a revived Beveridge Report for the poor. The house broke into laughter and applause as Whyte read the titles of the reports. This gesture led Conservative MP Nicholas Fairbairn to declare Whyte "Satanic".

Thatcher's speech was highly controversial. One clergyman present described it as "a disgraceful travesty of the gospel". The following day, the professor of practical theology at Edinburgh University, Duncan B. Forrester, objected on Radio Forth that the church had never countenanced the idea of an "individualist's paradise". The Church of England's Board of Social Responsibility issued a highly critical open letter. On the Catholic side, Cardinal Basil Hume merely remarked: "I already have to deal with one leader who thinks they're infallible."

Criticism was not restricted to voices within the churches. Much resentment was caused by the message "If a man will not work, he shall not eat" from a prime minister who had presided over an unprecedented rise in unemployment. Holding this speech before the Scottish church at a time when the Conservative party had just lost seats in Scotland and Thatcher's approval ratings north of the border were particularly low has been described as "political suicide". One journalist recalls: "It's said that this speech marked the beginning of the end for Conservative rule in Scotland, with many voices raised in opposition to what they regarded as an alien creed that abused classic Christian ideas in an effort to fashion a political manifesto." Thatcher's foreign policy advisor Charles Powell later admitted: "It was an unmitigated disaster and she should never have done it."

However, Thatcher's supporters believed that if the church invited her to speak, it should have expected her to talk about the religious aspects of her worldview. The Margaret Thatcher Foundation, which reproduces the full text of the speech on its website and characterises the nickname "Sermon on the Mound" as tasteless, rates it as having key importance as a statement of Thatcher's views on "civil liberties, education, taxation, family, race, immigration, nationality, religion & morality, social security, and welfare". Thatcher herself noted: "[W]e have had more requests for copies of that speech from all over the world than any other."

In 1989, the novelist Jonathan Raban made a detailed analysis of the address using the methodology of literary criticism, in particular studying how the vocabulary resonates with the language of English Methodism and of Scottish Presbyterianism, as well as its place in Thatcher's own political rhetoric. He discusses the allusions to Abraham Lincoln, the "Battle Hymn of the Republic" and Gilbert and Sullivan. He highlights the significance of the idiosyncratic "Judaic-Christian" (as opposed to Judeo-Christian) and the implied slighting of Islam. Raban rates the speech as a strong statement of Thatcher's ideas: "[N]o attack on its eccentric theology, its flawed logic, its mercilessly scant language can rob Mrs Thatcher's speech of the remarkable consistency of its vision. It is stamped throughout with her peculiar integrity, her plainspun way with big ideas, her scornful and impatient certitude." However, he concludes that the language of the address "has the unpleasant ring of a new and pertly unctuous thieves' slang".

• The full text of the speech on the website of the Margaret Thatcher Foundation
• The original broadcast footage on YouTube - N.B. a paragraph on religious tolerance has been edited out of this video.