King Charles III greets the public on arrival at Buckingham Palace

New head of state shakes hands with well-wishers after returning from Balmoral where Queen Elizabeth II died

Britain's King Charles III arrives back in London a day after the death of his mother, Queen Elizabeth II. AP

King Charles III greeted his new subjects with handshakes and smiles on Friday as he returned to Buckingham Palace a day after the death of his mother, Queen Elizabeth II.

Britain's new king spoke to well-wishers before walking through the gates of the palace, in a surprise addition to the carefully choreographed 10-day mourning period.

As mourners offered their condolences on the queen's death, and one woman leaned in to kiss him on the cheek, a small group of admirers struck up the tune of the amended national anthem, God Save the King.

The king, who arrived with his wife Camilla, now the queen consort, bowed his head as he inspected the flowers that mourners had left at the palace railings.

The couple were driven to the palace after landing at RAF Northolt, a military airfield in west London, on their return from the Balmoral estate in Scotland where the queen died on Thursday.

King Charles, 73, returned to the palace as sunshine broke out to replace the gloomy skies that had greeted mourners earlier on Friday as they left handwritten tributes and came to witness a moment of history.

While union flags are flying at half-mast during the 10-day mourning period, the royal standard was raised above Buckingham Palace to signal that a new monarch was in residence.

The king was expected to address the nation later on Friday.

Although he assumed the throne at the moment of the queen's death, a formal proclamation ceremony will take place early on Saturday with an Accession Council of senior politicians and functionaries.

As part of the theatre of the occasion, the proclamation will first be read out from a balcony at St James's Palace in London, then at the Royal Exchange in the city's financial centre and subsequently in Scotland, Wales and Northern Ireland.

Bells rang out from Britain's most historic churches on Friday as part of the nationwide tributes to the queen, whose 70-year reign was the longest of the monarchy's 1,000-year history.

The bells of Westminster Abbey, St Paul’s Cathedral, York Minster and those of other church towers tolled to salute the queen at midday.

A 96-gun salute, one for every year of the queen's life, followed an hour later at the Tower of London, Hyde Park, other British landmarks and Royal Navy ships at sea.

St Paul’s will hold a service of prayer and reflection on Friday evening at which Prime Minister Liz Truss is expected to attend and 2,000 members of the public were offered seats on a first-come-first-serve basis.

Ms Truss paid tribute to the queen at the start of a two-day mourning period in Parliament, during which MPs will assemble for a rare Saturday session to pay their respects.

Britain in mourning after Queen Elizabeth's death — in pictures

A well-wisher kisses the hand of King Charles III outside Buckingham Palace after the death on Thursday of Queen Elizabeth II. King Charles, who spent much of his 73 years preparing for the role, on Friday planned to meet the prime minister and address a nation grieving the only British monarch most of the world had known. He takes the throne in an era of uncertainty for his country and the monarchy itself. AP

King Charles III and Queen Consort Camilla arriving at Buckingham Palace, London, after travelling from Balmoral following the death of Queen Elizabeth II on Thursday. PA

King Charles and the queen consort outside Buckingham Palace. PA

King Charles and the queen consort view tributes left outside Buckingham Palace, London, after the death of Queen Elizabeth on Thursday. PA

King Charles greets well-wishers outside Buckingham Palace. AP

King Charles and the queen consort read messages left by mourners at Buckingham Palace in London. Queen Elizabeth II, Britain's longest-reigning monarch and a rock of stability through much of a turbulent century, died on Thursday, after 70 years on the throne. She was 96. AP

King Charles greets well-wishers at Buckingham Palace after the death on Thursday of his mother, Queen Elizabeth II. AP

King Charles and Queen Consort Camilla view tributes left outside Buckingham Palace after the death of Queen Elizabeth II. PA

Outside Buckingham Palace on the first day of public mourning after the death of Queen Elizabeth II. The queen's death at the age of 96 marks the start of a tumultuous 10 days for the UK in which a queen is buried, a nation will mourn its longest-reigning monarch, and a new king is proclaimed. Bloomberg

King Charles during a walkabout to view tributes left outside Buckingham Palace. PA

King Charles outside Buckingham Palace on Friday. AP

King Charles and Queen Consort Camilla surrounded by crowds of well-wishers in London. Reuters

The car carrying King Charles and the queen consort arrives at Buckingham Palace with the Union Flag at half mast. Getty Images

People gather at the Queen Victoria Memorial opposite Buckingham Palace on Thursday night after the death of Queen Elizabeth II. Reuters

People gather at the Queen Victoria Memorial opposite Buckingham Palace after the death of Queen Elizabeth II. PA

Mourners gather outside Buckingham Palace on Thursday night. PA

Tributes and candles left outside Buckingham Palace in London after the queen's death was announced. PA

Police officers stand among floral tributes left outside Buckingham Palace. PA

A member of the royal household staff posts a notice on the gates of Buckingham Palace announcing the death of Queen Elizabeth. AFP

Royal follower John Loughrey, wearing a Union Jack hat, photographs the official announcement of the queen's death. EPA

Mourners outside Buckingham Palace. Reuters

A man with a Union flag umbrella shelters from the rain near the Queen Victoria Memorial. AFP

Mourners on the Queen Victoria Memorial outside Buckingham Palace. PA

The crowds outside Buckingham Palace on Thursday night. PA

Mourners at the vigil outside Buckingham Palace. PA

Mourners at the vigil outside Buckingham Palace. PA

Londoners walk down The Mall that leads to Buckingham Palace on Thursday night. PA

Taxis lined up along The Mall leading to Buckingham Palace in London after the announcement of the death of Queen Elizabeth. PA

The advertising screens in Piccadilly Circus in London mark the death of the queen. Getty

An image of Queen Elizabeth II is displayed on The BT Tower in London. Getty

A bus stop on Tottenham Court road in London displays an image of the queen. Getty

Mourners gather outside Windsor Castle, Berkshire. PA

Flowers are left under the Queen Victoria statue outside Windsor Castle. PA

Candles and flowers form a makeshift memorial at the Queen Victoria statue outside Windsor Castle. PA

People lay floral tributes outside Balmoral Castle, Scotland, on Thursday night. EPA

People lay floral tributes outside Balmoral Castle, Scotland, Britain, 08 September 2022. EPA

People pay their respects at the gate of Sandringham House in Norfolk. PA

People pay their respects at the gate of Sandringham House in Norfolk. PA

“She was the rock on which modern Britain was built,” the prime minister said. “She bequeaths a modern, dynamic nation that has grown and flourished under her reign.”

Former prime minister Boris Johnson, one of the last people to see the queen when he formally resigned at Balmoral on Tuesday, said she had appeared “as radiant and knowledgeable and as fascinated by politics as ever”.

“Think what we asked of her … to be the figurehead of our entire system, the keystone in the vast arch of the British state,” Mr Johnson said.

Many sporting events were cancelled out of respect for the queen, including Premier League football fixtures and the second day of a Test match between England and South Africa's cricketers.

The beginning of the new monarch's reign will also bring a host of changes to practical and symbolic parts of life, from the face on coinage and banknotes to the new moniker of “His Majesty's Government”.