The King’s coronation service has begun, with the eyes of the world watching Charles and the Queen as their moment with history came a step nearer.

Charles and Camilla were welcomed at Westminster Abbey’s great west door by the Archbishop of Canterbury Justin Welby, who will anoint and crown the monarch, after travelling through the capital’s streets in a carriage procession.

Thousands of well-wishers lined the route the couple’s Diamond Jubilee Coach took from Buckingham Palace, with a few die-hard royalists sleeping in tents to secure the best spot to catch a glimpse of the King and Queen.

World leaders, prime ministers from overseas realms, foreign monarchy and the extended British royal family were seated inside the ancient place of worship.

Those invited included actress Dame Emma Thompson, musicians Lionel Richie and Nick Cave, presenters Ant and Dec and actresses Dame Judi Dench, Dame Maggie Smith and Dame Joanna Lumley.

Future kings, the Prince of Wales and his son Prince George, who will both play a role in the coronation, were in place and the Princess of Wales arrived with Princess Charlotte and Prince Louis.

The Duke of Sussex was seated in the third row, two rows behind William, but the Duchess of Sussex has remained at home in the US.

The King will become the 40th reigning monarch to be crowned at Westminster Abbey, the nation’s coronation church, since William the Conqueror was anointed monarch within its walls on Christmas Day 1066.

Charles and Camilla’s Diamond Jubilee Coach arrived in the midst of a Sovereign’s Escort provided by the Household Cavalry’s Blues and Royals and Life Guards with their shining breastplates and plumed helmets and led by the Household Cavalry Mounted Regiment band.

The monarch and his wife’s entrance through the west door was heralded by a fanfare from four State Trumpeters of the Household Cavalry and the abbey congregation stood as one.

A large ceremonial procession was lined up before the King and Queen with representatives of all elements of the nation’s ceremonial and spiritual life.

There were recipients of Orders of Chivalry and Gallantry, Heralds from the College of Arms in their colourful tunics, senior clergy associated with the monarchy and the glittering coronation regalia carried by leading figures.

Among those gathered was double Olympic Gold medallist Lord Coe, a member of the Order of Companions of Honour, Willie Apiata, New Zealand’s only living Victoria Cross recipient, and Lincolnshire farmer Francis Dymoke the King’s champion carrying the Royal Standard.

St Edward’s Crown, the 17th century artefact Mr Welby will use to crown Charles, was carried by General Sir Gordon Messenger, Lord High Steward of England.

With their lavish and unwieldy robes, the King and Queen walked single file along the nave of the abbey with Camilla ahead of Charles as the hymn I Was Glad As They Said Unto Me was sung.

Earlier, the King and Queen made their first appearance of coronation day when they travelled the short distance from their Clarence House home for final preparations at Buckingham Palace.

The Duke of York was driven down The Mall in a state car, with parts of the crowd booing as he went past.

Inside the ancient abbey, the church buzzed with noise as the congregation filed in and took their seats hours before the ceremony was due to start.

A smiling Dean of Westminster, Dr David Hoyle, in his vivid red clerical robe was seen hurriedly carrying the holy oil for the anointing down the length of the abbey from the altar through the quire, clutching the precious ornate silver vessel in both hands.

As anticipation mounted among royal fans, a group of republicans were arrested around 7.30am more than four hours before the coronation service began.

Footage on Twitter showed Graham Smith, chief executive of the anti-monarchy group Republic, being apprehended by police in St Martin’s Lane, Westminster.

Pictures appeared to show demonstrators in yellow “Not My King” T-shirts, including Mr Smith, having their details taken by officers.

Protest group Just Stop Oil also said approximately 13 demonstrators were arrested on The Mall, as well as five at Downing Street.

The King will be crowned during a coronation ceremony dating back centuries.

Cries of God Save the King will ring out around the abbey after St Edward’s Crown is placed on Charles’ head by Mr Welby.

The senior cleric said in a statement issued on the eve of the coronation that the ceremony served as “a powerful reflection and celebration of who we are today, in all our wonderful diversity”.

He said people will be struck by the “majesty and sacred wonder” of the service, but also hoped they would find “ancient wisdom and new hope”.

But in a change, the controversial “Homage of the People” element of the service has been toned down after there was widespread criticism of the new element.

Mr Welby will now “invite” a show of support from the congregation rather than a “call” to those in the abbey and elsewhere to swear allegiance to the King.

The event is the military’s largest ceremonial operation since Queen Elizabeth II’s 1953 coronation, with 9,000 servicemen and women deployed and 7,000 of these performing ceremonial and supporting roles.

The coronation service began with a new element when the King was greeted by 14-year-old Samuel Strachan, the longest serving chorister of the choir of the Chapel Royal, St James’s Palace.

The chorister, who attends the City of London School, welcomed the monarch in the name of the “King of Kings” – a reference to Jesus Christ – and Charles replied: “In his name, and after his example, I come not to be served, but to serve.”

The ceremony has five main elements: the Recognition; the Oath; the Anointing; the Investiture and Crowning; and the Enthronement and Homage, as well as the Queen’s coronation.

“Good save King Charles” rang out four times from the congregation during the Recognition, as the King turned to the points of the compass – east, south, west and north – and was presented to his people.

Before the King took the Oath – making a succession of promises, including to maintain in the UK the Protestant Reformed Religion established by law – the archbishop delivered a preface to Charles’s declaration – another first.

He told the congregation the Church of England, which is headed by the King, will seek to foster an environment where “people of all faiths and beliefs may live freely” – echoing the words of the late Queen and Charles.