Thousands of people are descending on London on Saturday hoping to catch a glimpse of King Charles as he prepares to be crowned in a historic ceremony, which will also be watched by millions around the world.

British military personnel marched over Westminster Bridge ahead of the spectacular ceremony.

Westminster Abbey has been the site of every British Coronation since that of William The Conqueror in 1066 and King Charles III and his wife, Queen Camilla, will follow in the footsteps of this grand tradition in a service themed “Called to Serve”.

The Service will be conducted by the Archbishop of Canterbury, the Most Reverend and Right Honourable Justin Welby, with faith leaders and representatives of the Hindu, Sikh, Muslim, Buddhist and Jewish communities processing through the Abbey ahead of the service.

Waterloo Station started buzzing into life shortly after 5 am local with hats, dresses, flags and even clothes for dogs emblazoned with Union Flags, Sky News reported.

They are all hoping to secure a spot to catch a glimpse of the King in the country's first coronation in 70 years.

Meanwhile, the first of more than 5,000 military personnel have arrived at Waterloo by train for the historic ceremony, it said.

They will lead processions accompanying the King and Queen Consort to and from Westminster Abbey.

The military personnel are members of the Royal Navy, Army, Royal Air Force and Commonwealth Forces, and are taking part in the biggest movement of military personnel on Britain's railways since Sir Winston Churchill's funeral in 1965.

The soldiers, sailors and aviators arrived to the sound of a special announcement recorded by the King and Queen Consort, which is being played at stations across Britain this weekend, the news channel said.

King Charles is preparing to be crowned in a ceremony which will be watched by millions of people at home and across the world.

Once at the Abbey, the King will be greeted by a congregation of around 2,200 – made up of heads of state and government, worldwide royalty as well as community champions.

Vice-President Jagdeep Dhankhar and his wife Dr Sudeep Dhankhar are representing India on the historic occasion and will be seated alongside other Commonwealth Heads of State.

In Green Park, groups of families and friends are hunkering down to watch the day’s events unfold on the big screen.

The park is awash with waves of red, blue and white as royal enthusiasts go all out for the occasion. Alexandra Hornyak, 57, travelled from Montreal, Canada.

“I've known for years that I would want to attend this day, and the day that it was announced, I was driving to the office, and my husband just called me and said ‘May 6’.

“I knew exactly what it was. And I jumped on the phone to get a hotel reservation and we went from there,” BBC quoted Hornyak as saying.

Karen Daly, 54, from Birmingham, said she "bought everything union jack, everything King Charles, we’ve got everything in stock".

The crowd on The Mall is cheering at any chance they get.

A massive security and policing operation, dubbed Golden Orb, is underway that will see 11,500 police officers on duty alongside more than 9,000 military personnel taking part in the ceremony.

Meanwhile, preparations have been in full swing at Buckingham Palace where staff have been adorning its famous balcony with red and gold draping ahead of the Royal Family's appearance later.

Military bands can be heard practising ahead of the procession while street cleaners have been working to ensure the area in front of the palace was ready.

The doors have opened to the general congregation assembling at Westminster Abbey, BBC reported.

Near Buckingham Palace, hordes of royal fans arrived in the early hours of the morning.

Wearing a bright red, blue and white wig, Heidi Roberts, from Surrey, said she’s come for the “happy atmosphere”.

“Just being with the crowd and having something to celebrate," she says. “I think we’re all mourning the Queen, and I think it’s a bit of a hangover from that," she said.

Anti-monarchy group Republic is among a number of groups which have organised protests on the day, media reports said.

It argues that the coronation pageant will cost tens of millions in taxpayers' money and points out that many families and households are struggling with spiralling costs as these celebrations take place.

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