Emperor Naruhito and Empress Masako of Japan have been greeted at Buckingham Palace by King Charles III, Queen Camilla and the Prince of Wales.

The ceremonial welcome marks the start of a three-day state visit to the UK.

The King, in the first state visit since his cancer diagnosis, stood on the podium to greet the emperor and empress.

In the blazing sunshine on Horse Guards Parade the Japanese royal couple were able to observe the guard of honour.

In what must have been sweltering bearskins, the 1st Battalion Welsh Guards lined up on the parade ground gravel. Bands played music for the Japanese visitors.

Also greeting the Japanese emperor and empress were Prime Minister Rishi Sunak, Foreign Secretary David Cameron, Home Secretary James Cleverly dressed in morning suits, in one of the last ceremonial events before the election.

For this formal diplomatic moment there was not any public crowd on Horse Guards. Instead there were ranks of cameras and journalists and security staff watching from the roofs of Whitehall.

The carriages then travelled up past the crowds on the Mall towards Buckingham Palace.

The Princess Royal is absent from the visit, after being admitted to hospital following a head injury thought to have been caused by a horse.

State visits are a mix of ancient pageantry and modern international politics, with the red carpet being rolled out for important visitors.

The visit by the emperor and empress is intended to reinforce military, scientific and cultural links between the UK and Japan.

It is the first by a Japanese head of state since 1998. It began with a formal royal greeting at Horse Guards Parade followed by a procession to Buckingham Palace.

State visits during a general election are unusual. In the past, they have been rescheduled to avoid a clash with political campaigning.

The Japanese royal couple will not make a trip to Downing Street because of the general election campaign.

But the Japanese visit – planned before the election was called – has gone ahead without the usual meeting with the prime minister in 10 Downing Street.

A centrepiece of this diplomatic flattery is the state banquet in the lavish surroundings of the ballroom of Buckingham Palace.

The King will toast his visitors at such events and make a speech in honour of his guests.

The emperor will then reply.

Prime Minister Sunak and Labour leader Keir Starmer will be at the state banquet on Tuesday evening, in one of the last such formal occasions before next week’s election.

Tomorrow night, the two party leaders will take part in a head-to-head TV debate.

The emperor and empress’s programme of visits over the next few days will include Westminster Abbey, the Francis Crick Institute, Kew Gardens and the Royal College of Music.

They will lay a wreath on Elizabeth II’s tomb, in St George’s Chapel, Windsor.

And on Friday, after the state visit has ended, they will make a nostalgic return to their former colleges at Oxford University, where they were both students.