King Charles shakes hands with well-wishers in queen's queue

• Queen Elizabeth's grandchildren to hold vigil
• Line to see queen's coffin stretches to 16 hours
• World leaders start arriving in London for funeral

King Charles shook hands and spoke to well-wishers queuing for hours in central London on Saturday to file past the coffin of his mother, Queen Elizabeth, after thanking emergency workers who are helping to stage the late monarch's funeral.

To cheers of "hip, hip, hurrah" and shouts of "God save the King", Charles walked alongside part of the queue waiting to see the queen's lying-in-state, asking those lining up how long they had been there and whether they were warm enough.

His son and heir, Prince William, also chatted to the crowds wanting to honour the queen who died aged 96 last Thursday.

People are continuing to flock to central London, adding to the already hundreds of thousands who have filed past the coffin in a solemn stream, to pay their respects to Britain's longest-reigning monarch - a testimony to the affection in which she was held.

With preparations for the Elizabeth's funeral on Monday well under way, the king visited police headquarters to thank emergency services workers involved in the planning.

London's police force said on Friday the funeral would be the biggest security operation it has ever undertaken as prime ministers, presidents and royals come together.

Underscoring the risk, police said one man had been detained and arrested after a witness told Sky News he "ran up to the queen's coffin". Footage showed a man being pinned to the ground by police officers and taken away.

Charles was also due to greet leaders of the 14 countries where he is head of state such as Canada and Australia, and have lunch with the governors general - the people who represent the monarch in overseas realms - at Buckingham Palace.

VETERANS SALUTE
By lunchtime, Britain's culture ministry said the waiting time to reach the historic Westminster Hall where Elizabeth's body lies in state, with her oak coffin on a purple-clad catafalque, draped in the Royal Standard and with the bejewelled Imperial State Crown on top, was up to 14 hours.

In the silent hall, some mourners wept, many were tearful while current soldiers and veterans saluted their former commander-in-chief. Others fell to their knees.

Canadian Prime Minister Justin Trudeau and Australian Prime Minister Anthony Albanese were among the dignitaries to pay their respects.

Earlier, the government had said it would pause entry to the queue if demand became too high, adding at 1 a.m. (0000 GMT): "Please do not travel."

New friendships, acts of kindness and the struggles of standing in line for hours, sometimes overnight, have come to define what has become known as just "the queue".

Film-maker Matthew West described how a military man was offered the chance to get to the front but declined. "That was the highlight. The lowlight was when we stood still for two hours and I lost the will to live."

The death of the queen at her summer estate in the Scottish highlands has sparked an outpouring of emotion across the country and 10 days of choreographed events.

Having laid at rest in the Scottish capital for 24 hours the coffin was flown south to London, where tens of thousands of people crowded onto a normally busy road in driving rain to observe the flag-draped casket being driven to Buckingham Palace.

On Friday night, Charles joined his three siblings - Princess Anne and Princes Andrew and Edward in a silent vigil at the coffin while their eight children, including William and Harry, will form their own ceremonial guard later on Saturday.

FUNERAL PLANS
The queen's children have described being overwhelmed by the reaction to their mother's death.

The state funeral, to be attended by nearly 100 presidents and heads of government including those from the United States, France, Australia, Japan, Jamaica and Canada, is likely to be one of the biggest ceremonial events ever held in Britain.

Soldiers took part in early morning rehearsals in Windsor, where the queen's coffin will be driven to after the funeral at Westminster Abbey. Marching bands playing music and Grenadier Guards, who wear a tall bearskin hat on ceremonial duties, were seen marching down the High Street in preparation.

Later on Saturday, the focus will switch to the younger royals and their vigil.

William and his brother Harry, who have grown apart in recent years after Harry moved to the United States, will both stand guard at the coffin in military uniform.

Harry served two tours of duty with the British Army in Afghanistan but so far has appeared in processions in morning suits after he lost his honorary military titles when he stepped back from public royal duties.

The two brothers will be joined by their cousins - Peter Phillips and Zara Tindall, the children of Princess Anne, Princesses Beatrice and Eugenie, the children of Prince Andrew, and Louise and James, the children of Prince Edward.