The chapel, built by Henry VIII, has Mary Tudor’s heart buried beneath the chancel step, was the setting for Charles I receiving the sacrament before his execution, and in 1997 the coffin of Princess Diana lay before the altar, waiting for the funeral.

On Wednesday her grandson was christened by the Archbishop of Canterbury, in a small, intimate gathering chosen for their closeness to his parents rather than tradition or prerogative.

However, the ceremony itself was steeped in history.

The prince was baptised with water from the River Jordan, kept in the Lily Font, a silver font commissioned by Queen Victoria for the birth of their first child – it has been used at every royal christening since.

He was wearing a replica of the royal christening robe, also made in 1841 for Queen Victoria’s eldest daughter – five years ago the Queen commissioned a carefully-made copy in order to preserve the historical original. It was handmade in fine Honiton lace lined with white satin.

The parents chose two hymns for the christening – ‘Breathe on Me, Breath of God’ and ‘Be Thou My Vision’.

Pippa Middleton read from the gospel according to St Luke (“Suffer little children to come unto me”) and Prince Harry read from St John (“I am the true vine, and my Father is the husbandman”).

There were also two anthems: ‘Blessed Jesu! Here we Stand’ and ‘The Lord Bless You and Keep You’. ‘Blessed Jesu’ was written for William’s baptism in 1982.The couple also chose some organ music: Bach’s Gantasia in G, and Widor’s Toccata from Symphony No 5.

A few hundred keen royalists gathered outside the palace, draped in Union Jacks, but they were disappointed as Prince William, Kate and the baby nipped in another gate.

However, they did get to wave their flags at the other guests: the Queen and Prince Phillip were among the small group, as well as Prince Charles, Camilla and Prince Harry, and they were greeted by a salute from the Queen's Guard.

Kate’s parents Michael and Carole Middleton and her siblings James and Pippa, and the seven godparents and their partners, were the only other guests.

Fierce speculation had surrounded the identity of the godparents, with many predicting the couple would abandon tradition and choose from their close friends.

The speculation proved largely correct. The godparents were:

- Oliver Baker, a university pal of the duke and duchess who lived with them in their last year there,

- Emila Jardine-Paterson, a schoolfriend of Kate’s and an interior designer who is said to have advised the couple on renovating their Kensignton Palace apartments.

- Hugh Grosvenor, son of the Duke of Westminster and one of Britain’s richest people aged only 22,

- Jamie Lowther-Pinkerton, a private secretary to William and a mentor over many years,

- Zara Tindall, William’s cousin (the only member of the royal family in the list of godparents), and

- William van Cutsem, a childhood friend of William – whose father was a close friend of Prince Charles.

They were joined by the most symbolic and moving godparent: Julia Samuel, a close friend of Princess Diana and founder of a child bereavement charity of which William is patron.

The choice was interpreted as a desire for Prince George to have someone close who could tell him about the grandmother he never knew.

Ingrid Seward, editor of Majesty Magazine, told the BBC royal christenings were usually small and private affairs.

She said the choice to move away from the old ‘dynastic’ godparents was not unexpected, but she was surprised that not even one European royal had made the cut – William was said to be very close to his godfather King Constantine of Greece.

Previous royal christenings have taken place at Buckingham Palace, but the Chapel Royal was not a surprising alternative.

St James’ Palace is the senior royal palace, as trivia buffs are well aware – and the chapel itself was the venue for the wedding of Queen Victoria and Prince Albert in 1840.

After the service, the Prince of Wales and the Duchess of Cornwall were to host a private tea in Clarence House.

Guests were served slices of the christening cake – a tier taken from William and Kate’s wedding cake.