The death of the Queen has plunged a shocked nation into mourning for its longest-reigning monarch, with the new King expressing the “greatest sadness” at the loss of his “beloved mother”.

As Britain and the rest of the world digested the news, tributes flooded in from around the globe, hailing the Queen’s unwavering commitment to serving her country and the Commonwealth.

King Charles III acceded to the throne immediately on the death of Elizabeth II, who died peacefully at the age of 96 in the sanctuary of Balmoral Castle on the afternoon of Thursday September 8.

One of the first acts of the new monarch – whose chosen title was confirmed by Prime Minister Liz Truss – was to speak of his grief and highlight the “respect and deep affection” in which the Queen was “so widely held”.

World leaders, celebrities and ordinary people – gathered at the gates of Buckingham Palace, Balmoral and Windsor Castle – all paid tribute, with US president Joe Biden describing her as “a stateswoman of unmatched dignity”.

Ms Truss – just two days into her role – heralded the late monarch’s “great legacy” outside Downing Street as news of the end of the New Elizabethan era became a reality.

“Queen Elizabeth II was the rock on which modern Britain was built. Our country has grown and flourished under her reign,” she said.

“Britain is the great country it is today because of her.”

Charles, whose wife Camilla is now Queen, said in a written statement: “The death of my beloved Mother, Her Majesty The Queen, is a moment of the greatest sadness for me and all members of my family.

“We mourn profoundly the passing of a cherished Sovereign and a much-loved Mother.

“I know her loss will be deeply felt throughout the country, the Realms and the Commonwealth, and by countless people around the world.

“During this period of mourning and change, my family and I will be comforted and sustained by our knowledge of the respect and deep affection in which The Queen was so widely held.”

The nation came to a halt to mourn its former monarch, with the Mercury Prize for leading musicians postponed and play at the PGA Championship golf event at Wentworth suspended, amid wall-to-wall coverage on TV channels.

Buckingham Palace made the official announcement at 6.30pm with a brief 26-word statement saying: “The Queen died peacefully at Balmoral this afternoon.

“The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow.”

In other developments:

– Camilla automatically became the Queen, as the wife of the King.

– William, as the Duke of Cornwall and Cambridge, is the heir to the throne, and Kate is the Duchess of Cornwall and Cambridge.

– The new King is expected to address the nation on television on Friday evening.

– An Accession Council – the formal proclamation of Charles as King – will take place on Saturday.

The royal family including the Queen’s four children – Charles, the Princess of Royal, the Duke of York and the Earl of Wessex, and grandsons the Duke of Cambridge and the Duke of Sussex – cleared their diaries and rushed to be by her bedside when it became clear the monarch was gravely ill.

Royal doctors had recommended she remain under medical supervision, with the Palace issuing an unusually detailed update earlier in the day, saying royal doctors were concerned for her health.

The Duchess of Sussex, whose troubled relationship with the monarchy has long been documented, remained down south after initially planning to accompany Harry to Scotland.

The Duchess of Cornwall and Cambridge, as Kate’s title is now, stayed in Windsor – less than a 10-minute walk from Meghan’s Frogmore Cottage residence – with her children Prince George, Princess Charlotte and Prince Louis having had their first full day at school.

The Queen served as head of state for more than 70 years, dedicating her life to royal duty.

Her reign eclipsed all others in British history, and the majority of the population has known no other monarch.

Members of the public began to leave flowers at the gates of Buckingham Palace, where officials carried a notice confirming the Queen’s death to the gates and the flag was lowered to half mast.

There were tears and many well wishers sang the national anthem.

One onlooker said the Queen is “all we’ve ever known”.

Behind the scenes, the long-held London Bridge plans for the Queen’s death are being rapidly put into action, setting out the next 11 days according to a strict timetable which will feature a lying in state and then the solemnity and grandeur of a state funeral.

The arrangements have a more complex factor due to the Queen’s death being in Scotland – and have triggered Operation Unicorn, the contingency plans in case of such an event.

Members of the royal family will be expected in the coming days to hold a poignant vigil around the Queen’s coffin in St Giles’ Cathedral in Edinburgh, and the Queen’s coffin will have to be transported by RAF plane back to London.

She is expected to lie in state in a few days’ time in London, with her funeral held in Westminster Abbey in central London, most likely on Monday September 19.

On Friday, gun salutes – one round for every year of the Queen’s life – will be fired in central London.

The King and his Queen Consort Camilla will return to London, with the monarch holding his first audience with the Prime Minister.

In the evening, the King will address the nation on television, paying tribute to his mother and pledging to serve as head of state.

The PM and senior ministers will attend a public service of remembrance at St Paul’s in central London.

On Saturday morning, a Accession Council will meet at St James’s Palace in London to formally proclaim Charles as the new sovereign.

The first public proclamation of the new sovereign will then be read in the open air from the Friary Court balcony at St James’s Palace by the Garter King of Arms.

Charles will hold audiences, and the media will be briefed by the Earl Marshal, who is in charge of the accession and the Queen’s funeral, on the coming days.

Alongside her public duties, the Queen was a mother of four, grandmother to eight and great-grandmother of 12, and the royal family is now grieving for its matriarch.

Anne, Edward and Sophie will undoubtedly issue poignant tributes, with William, Harry and other grandchildren expected to follow suit.

London is expected to be packed by mourners, with the Government concerned its infrastructure will be overwhelmed with thousands expected to descend on the capital for the momentous occasion.