King Charles III began his first speech as monarch by recalling the pledge made by his mother on her 21st birthday in 1947. Speaking from Cape Town on the occasion of her 21st birthday, Princess Elizabeth declared ‘before you all that my whole life, whether it be long or short, shall be devoted to your service and the service of our great imperial family’. She ended by saying: ‘God help me to make good my vow and God bless all of you who are willing to share in it.’

We know now that the Queen was given a long life during which the world, as it was when she was 21, was transformed. Cape Town is now part of an independent post-apartheid South Africa. The Empire dissolved, to be replaced by a Commonwealth. As the world shifted, the Queen embraced new themes but her commitment to ‘sacrifice and service’ remained constant.

She was also explicit on numerous occasions that her ‘inspiration and anchor’ was Jesus Christ. As she said in her Christmas message for 2014, Christ has been ‘a role model of reconciliation and forgiveness, he stretched out his hands in love, acceptance and healing. Christ’s example has taught me to seek to respect and value all people of whatever faith or none’.

These words reflect a firm personal faith nourished by the experience of prayers and Bible-reading with her mother whose own faith had sustained her during the darkest days of the war and the early death of King George VI. The Queen Mother used to describe her visits to Dean Matthews of St Paul’s and his suggestions for spiritual reading. Some of the books he recommended were adventurous for the time and, looking back, the Queen Mother asked: ‘Does anyone read Mr Middleton Murry now?’

Influenced by her mother, Elizabeth II also shared with her great-great grandmother Queen Victoria a down-to-earth, liberal Christian faith expressed in a disciplined but unfussy style of piety.

In her Journal entry for 8 August 1852, Queen Victoria wrote: ‘Albert told me much about an interesting book he is reading, The Life of Jesus by Strauss – Dinner as yesterday.’ Victoria was immensely curious about many things and her journal is frequently expansive about Highland scenery, foreign travel and the theatre, but her interest in speculative divinity was very limited.

There are comparisons to be made with the personal faith of her great-great granddaughter Elizabeth II, who left theological debate to Prince Philip. Constitutionally, however, she took her responsibilities seriously.

The constitutional position of the Crown vis-à-vis the established churches of England and Scotland emerged out of the broils of the early modern period. The monarch is still described on our coins as ‘Defender of the Faith’. Ironically, it was a title originally conferred on Henry VIII by Pope Leo X in 1521 after Henry, allegedly with the assistance of Thomas More, published an attack on the teachings of Martin Luther.

The Pope rescinded the title after the breach with Rome, but it was re-conferred by parliament. In 1534 the Act of Supremacy recognised the monarch as ‘Supreme Head on Earth’ of the Church of England. In the religious settlement which followed the accession of Elizabeth I, the Queen was described in marginally less exalted terms as ‘Supreme Governor’. The role was re-affirmed at the Restoration of Charles II and more closely defined in the constitutional settlement which followed the deposition of James II. Accordingly, the second Elizabeth was anointed by the Archbishop at the Coronation of 1953 and took an oath to ‘maintain and preserve inviolably the settlement of the Church of England and the doctrine, worship, discipline and government thereof as by law established in England’.

The coronation has been described as an ‘act of national communion’ at a time when a majority of the English population were baptised members of the Church of England. Regular Sunday worship declined in the second half of the 20th century and the trend accelerated after 1968. The reach of the church through its occasional offices and charitable work is of course much wider, but still those who profess a commitment to the Church of England are now a minority.

The formal position continues to be that the monarch must be an Anglican and is responsible for appointing archbishops, bishops and deans on the advice of the prime minister. Gordon Brown, however, was unwilling to continue to be involved actively in the process. Nowadays, a synodical body, the Crown Nominations Commission, sends a single name to No. 10 for onward transmission to the Queen.

Queen Victoria would have been appalled. Her prejudices had a substantial impact on appointments, even though on the whole she disliked the episcopal order. When a church delegation came to wish her well on the occasion of the Diamond Jubilee, she described them as a ‘very ugly party’ and frankly avowed: ‘I do not like bishops.’

By contrast, Elizabeth II conducted herself with studious impartiality as Supreme Governor. All newly appointed bishops did personal homage and every year one of the bishops was invited to join the royal party during the monarch’s annual New Year visit to Sandringham. Part of the programme was to deliver a sermon in the parish church and visiting prelates were always advised to preach a plain parochial sermon but be prepared to be catechised afterwards by Prince Philip. The Queen did not discriminate between high church or low church, but it was clear that what she really liked was short church.

All royal palaces have their chapels. In 2013, in a powerful symbol of continuity, four generations of the royal family gathered in the Chapel Royal of St James’s Palace for the baptism of Prince George in the Lily Font, which was commissioned by Queen Victoria at a cost of £401.

The Chapel Royal is also the scene for surviving fragments of the once elaborate royal liturgical calendar. At Epiphany, for example, the monarch’s representatives offer gold, frankincense and myrrh at the altar to recall the gifts offered by the wise men to the Christ child. At the end of what is a solemn service the youngest child of the Chapel choir challenges the Queen’s representative, who is usually a very high-ranking military officer, for breaking a rule established by James I that spurs should not be worn in the Chapel. The child demands ‘the customary forfeit’ and after he has successfully negotiated the gamut, the monarch’s representative pays the fine.

The Royal Maundy service is another survival. Monarchs used to wash the feet of the poor in imitation of Jesus Christ who at the Last Supper washed the feet of his disciples. In the modern ceremony revived by George V, a number of elderly people receive gifts of specially minted Maundy money. The Queen took such ceremonies with utter seriousness but she combined dignity with a delightful sense of humour. At one Maundy event she asked a centenarian to what he attributed his great age, and she enjoyed recalling his response: ‘I am a Norwich football club supporter and I only drink alcohol when they win.’

As well as celebrating the symbolic continuities, the Queen also began new traditions. Beginning in 1970, every five years she attended the inauguration of new sessions of the General Synod, the governing body of the Church of England.

She was always reticent about her personal opinions about people and policies. She was reluctant even to divulge whether she had a favourite hymn, knowing that she would be condemned ever afterwards to hear it on every occasion.

During the Diamond Jubilee in 2012, in a speech at Lambeth Palace the Queen was explicit about her own view of the role of the Church of England in a multicultural country. ‘The concept of our established church is occasionally misunderstood and I believe commonly underappreciated. Its role is not to defend Anglicanism to the exclusion of other religions. Instead, the church has a duty to protect the free practice of all faiths in this country.’

The Queen believed that the ‘Defender of the Faith’ should be the friend and protector of all the faiths which make up the national community. She was an assiduous visitor to temples, gurdwaras and mosques. The idea, however, that you could slip the Christian anchorage in favour of a generalised benevolence to all religions was not one she instinctively favoured. To be simply a ‘Defender of Faith’, rather than the Faith, suggests that one occupies an elevated position in which all faiths are seen as more or less adequate local editions of something vaguely lying beyond them all. Spiritual progress and deeper appreciation of other traditions comes from the serious and disciplined choice of a particular way to follow. The Queen was intensely disciplined in every aspect of her life including in its spiritual dimension. Wherever she was, Sunday worship was a priority.

This was also true in Scotland, where the monarch’s relation to the Church of Scotland was markedly different from the situation in England. The 1707 Act of Union affirmed the monarch’s duty ‘to preserve the settlement of the true Protestant religion as established by the laws made in Scotland’. When the Queen worshipped in Scotland, it was as an ordinary member of the Presbyterian Kirk.

The ‘British’ project of the period of the Act of Union was underpinned by the assertion of the Protestant identity of the new United Kingdom. Elizabeth II was also able to develop close relations with Catholic churchmen. She received Pope John Paul II at Buckingham Palace and visited the Vatican on numerous occasions. The Queen’s view that ‘gently and assuredly, the Church of England has created an environment for other faith communities and indeed people of no faith to live freely’ would have startled previous generations.

The Queen always kept in mind that what she said, no matter how commonplace, would be remembered for a lifetime. She was astonishingly observant but not loquacious. St Bernard’s advice to a young abbot comes to mind. ‘Notice everything; keep silent most of the time; correct a few things and cherish the brethren.’ She communicated all this not so much by words as by a quality of presence and attention which brought value to every encounter, however small.

The simplicity and brevity of her speeches, in which every word was weighed, did have extraordinary power, but there was another dimension. At events such as Lady Thatcher’s funeral, amid the tension and complex emotions of the occasion, her hieratic stillness as she stood on the steps of St Paul’s watching the departure of the coffin conveyed more eloquently than any words could that at the centre of national life there was a calm confidence and that the ship of state had an anchor.