Thanks to Meryl Streep and her movie The Iron Lady there is a renewed surge of interest in the life and times of Margaret Thatcher. Whatever one thinks of this biopic (Streep superb, storyline superficial, is the verdict of your High Spirits movie critic), there is one regrettable omission. There is not a single mention or scene highlighting one of the most important influences on Margaret Thatcher — her faith.

As a recently commissioned Thatcher biographer, I have been digging into this aspect of the Iron Lady with increasing fascination. Her faith journey, like her life, began in the English provincial town of Grantham. Her father, Alfred Roberts, was the owner of two grocery stores, but at the time of Margaret’s birth he was much better known as a local preacher.

Under her father’s tutelage, the young Margaret Roberts was brought up as a Wesleyan Methodist, attending church four times on a Sunday. Understandably she found this “too much of a good thing” and kicked against such excessive piety. But she was an admirer of preaching that had “intellectual substance.” Her father’s sermons fell into this category, as is clear from his handwritten notes for those of them that survive in the Thatcher archives at Churchill College, Cambridge.

Alfred Roberts was no Bible-bashing evangelical. His theology was full of surprises. He rejected fundamentalism. He was liberal in doctrine and ecumenical in reaching out across denominational boundaries. One of his key themes was the link between personal responsibility and spiritual dedication. What he preached, his daughter later practiced. “You must yourself believe intensely and with total conviction if you are to persuade others to believe,” were his words from a Grantham pulpit. They became her credo as a conviction politician.

The Methodists of the mid-20th century linked their religious beliefs to the political concerns of the day. But for Margaret, faith was a moral compass, not a political agenda. She was an active member of the John Wesley Society at Oxford University from 1943 to 1947. Like her father she delivered sermons. One of them on the text “Seek ye first the Kingdom of God” made a strong impact on the congregation of an Oxfordshire village. She was a preacher long before she became a politician.

After her marriage to Denis (also a believer) in Wesley’s City Road chapel in London, she moved from Methodism to Anglicanism without changing her spiritual convictions, her prayer life, or her Bible reading. In accordance with the conventional approach of English politicians, she said little during her early career about her religion. But she practiced it in terms of frequent churchgoing and occasional displays of biblical knowledge. On a visit to the Soviet Union in the 1960s she was shown a sculpture of a blacksmith beating a sword with a hammer. “That represents communism,” said the guide. “No it doesn’t,” retorted Mrs. Thatcher, “it’s from the Old Testament, ‘And they shall beat their swords into ploughshares and their spears into pruning hooks.'” Trust the preacher’s daughter to know Isaiah 2:4 by heart!

Once she became prime minister, she gradually lifted the veil on her religious convictions. One interviewer who pried some interesting faith disclosures from her was the mystical author and traveler Laurens van der Post. “The values of a free society like ours come from religion,” she told him, “they do not come from the state.” Explaining to him that the key value was the right of personal choice, the free will that linked the heavenly and earthly kingdoms, she cited the hymn “I Vow to Thee My Country.” It included, as she reminded him, the lines:

And soul by soul and silently her shining bounds increase,
And her ways are ways of gentleness, and all her paths are peace.

“There is the message,” she declared, “soul by soul.”

Margaret Thatcher did not neglect her journey of the soul during her years in power. To the astonishment of her staff at 10 Downing Street, she spent several weeks in 1983 rereading every book in the Old Testament. She decided that her favorite scriptures were Psalm 139: O God Thou has searched me out and known me, and Psalm 46: God is our hope and strength: a very present help in trouble. A few months later, in the middle of the most dramatic terrorist attack of her premiership, the Brighton bombing of October 1984, she did indeed find God to be “a very present help in trouble.” Soon after clambering out of the wreckage of the hotel, she writes in her memoirs, The Downing Street Years, she “could only think of one thing to do. Crawfie [her closest personal aide] and I knelt by the side of our beds and prayed for some time in silence.”

MARGARET THATCHER WAS NOT SILENT on the subject of her faith. She did not wear it on her sleeve but her occasional speeches on the subject were revealing. She knew her Bible but did not see it as a guide to day-to-day political leadership. “I never thought that Christianity equipped me with a political philosophy but I thought it did equip me with standards to which political activity must, in the end, be referred,” she said, citing Christ’s instructions to “render unto Caesar the things that are Caesar’s.” She thought that wealth creation was more important than welfare when it came to encouraging philanthropy in order to combat poverty. The parables of the Good Samaritan and of the Talents were central to her beliefs. “No one would remember the Good Samaritan if he’d only had good intentions; he had money as well,” she told one TV interviewer.

Such views did not endear her to the liberal establishment of the Anglican Church. She took them head on in an address to the (more conservative) General Assembly of the Church of Scotland in 1988. One of her themes was that it was not the role of the churches to enter into political debate. She thought they should be concerned with “spiritual redemption, not social reform.”

Dismayed by what she not-so-privately described as “the wetness” of the Church of England, she increasingly drew her theological inspiration from Catholic writers, particularly Michael Novak. The chief rabbi of British Judaism, Immanuel Jakobovits, was the spiritual leader she most admired. She appointed him to the House of Lords with far greater enthusiasm than she elevated the majority of English bishops who sit there as “Lords Temporel” by constitutional right.

Margaret Thatcher thought about faith issues far more deeply than any modern British prime minister. Her father’s teachings, buttressed by a lifetime of spiritual reading, were important navigation points throughout her journey. In an ideological sense she never left the Methodism of her youth. Her quest for “intellectual substance” in a faith of moral certainty was always an interest and at times a passion. Perhaps she wanted the substance to fit too neatly into a box that Alfred Roberts had designed, but that was her worldview. “The fundamental reason for being put on earth is so to improve your character that you are fit for the next world,” she told the BBC Today program in 1987. She had a better shot at this moral and spiritual target than you would ever guess from seeing The Iron Lady.