A carpet of flowers will greet mourners arriving at St George’s Chapel for the Queen’s Committal service.

The royal family will bid farewell to their beloved matriarch in the gothic chapel on the grounds of Windsor Castle in a service attended by around 800 people.

Members of the congregation are expected to include the late monarch’s nearest and dearest, her household staff past and present, and foreign royal families.

A wreath from Number 10, signed by Prime Minister Liz Truss, sits close to the door of the chapel, and says: “For a lifetime of devotion and duty we offer our deep and sincere gratitude.”

Flowers of all kinds cover the area around the chapel, from bouquets of red roses to pink lilies to potted plants to wreaths from foreign royals.

Inside one of the main entrances to the chapel, a floral arrangement of white blossoms sits in full bloom.

Among the flowers in the chapel were lilies, dahlias, roses, and greenery including Eucalyptus and other greenery picked from Home Park.

The service, with a strong thread of tradition running throughout, was discussed with the Queen over a number of years and all the prayers and hymns were chosen by her – apart from one.

The Queen left one hymn to be chosen at the time, and after a discussion between the King and the Dean of Windsor David Conner, the hymn chosen was Westminster Abbey adapted from the Alleluyas in Purcell’s O God, Thou art my God.

Much of the service will have a feel of looking back, repeating what has gone before, a feeling of coming full circle, with perhaps a sense of the consistency and constancy which the Queen will forever be remembered for.

Prior to the final hymn, the Imperial State Crown, the Orb and the Sceptre will be removed from the coffin by the Crown Jeweller and, with the Bargemaster and Serjeants-at-Arms, will be passed to the Dean who will place them on the altar.

The removal of the crown from the coffin to the altar is poignant, because in 1953 the crown was taken from the altar in Westminster Abbey and placed on the Queen’s head, marking the start of a 70-year reign.

At the end of the final hymn, the King will place The Queen’s Company Camp Colour of the Grenadier Guards on the coffin.

At the same time, The Lord Chamberlain will “break” his Wand of Office and place it on the coffin.

This is to create a symmetry with the three Instruments of State that have been removed.

The coffin, which will be placed on a catafalque draped in purple velvet will be slowly lowered down into the royal vault as the Dean of Windsor says: “Go forth upon thy journey from this world, O Christian soul.”

The Sovereign’s Piper will play a lament, A Salute to the Royal Fendersmith, from the doorway between the Chapel and the Dean’s Cloister during which he will walk slowly towards the Deanery in the Cloister so that the music inside the Chapel gradually fades.

During the service, the King will sit in the seat which was occupied by the Queen when she came to the chapel, positioned closest to the altar.

Tradition will run through the service in its music as it will feature several pieces that were also heard at the Duke of Edinburgh’s funeral and other major royal events.

JS Bach’s Schmucke Dich, O Liebe Seele – Adorn Yourself, O Dear Soul – (BWV 654) a piece for organ, will be played with a number of others as the mourners wait for the service to begin.

Another will be Vaughan Williams’ Rhosymedre, a firm favourite with the royal family with the music being performed at the wedding of Diana, Princess of Wales and Charles, and at Philip’s funeral.

Nimrod by Sir Edward Elgar was heard at the Queen’s coronation in 1953 and will also be played before the committal begins.

Lord Sentamu, the former Archbishop of York, was reportedly part of the team which helped devise the original order of service for the Queen’s state funeral.

The cleric told BBC News the Queen knew the psalms by heart and Psalm 121 – also featured at the Queen Mother’s Funeral in 2002 – will be sung at her committal.

The service will end with Bach’s Prelude and Fugue in C Minor (BWV 546) played after the national anthem, which was also heard at the end of Philip’s funeral.

Prayers will be said by the Rector of Sandringham, the Minister of Crathie Kirk and the Chaplain of Windsor Great Park, and by the Dean of Windsor.

The Choir of St George’s Chapel – made up of 11 men, one woman and 13 boys – will sing during the service and will be conducted by James Vivian, director of music, and the organ will be played by Luke Bond, assistant director of music.

Much of the music at the service has been composed by Sir William Harris, who served as the organist at St George’s Chapel between 1933 and 1961, taking in much of the Queen’s childhood.

The young Princess Elizabeth would often visit the organ loft to watch Sir William play, and it is believed he taught her to play the piano.

The Dean of Windsor’s bidding, which was written after the Queen’s death, includes the words: “Here, in St George’s Chapel, where she so often worshipped, we are bound to call to mind someone whose uncomplicated yet profound Christian faith bore so much fruit.

“Fruit, in a life of unstinting service to the Nation, the Commonwealth and the wider world, but also (and especially to be remembered in this place) in kindness, concern and reassuring care for her family and friends and neighbours.

“In the midst of our rapidly changing and frequently troubled world, her calm and dignified presence has given us confidence to face the future, as she did, with courage and with hope.”

The Queen will be buried with her late husband Prince Philip in the King George VI Memorial Chapel.

A private burial service, attended by the King and other members of the royal family, will take place on Monday evening.