The King was joined by his brothers Andrew and Edward and sister Anne, as well as Princes William and Harry, for the sombre procession from Westminster Abbey.
Some 98 sailors pulled the ceremonial gun carriage, while another 40 marched behind.
Guardsman and members of the Armed Forces followed, all walking at 75 paces a minute.
The Queen Consort, Princess of Wales, Duchess of Sussex and Countess of Wessex followed by car.
There was a hush from the crowd – 30-deep in places – in Whitehall as the procession moved past the Cabinet War Rooms, the Cenotaph and Downing Street.
Then every head in the crowd turned as one as the Queen’s coffin moved along the route in front of her old home Buckingham Palace, with well-wishers spontaneously erupting into rounds of applause and shouts of “hip, hip hooray”.
But members of the Royal Family remained expressionless as they circled round the Queen Victoria Memorial.
Further along, some people emerged from balconies and windows, clad in black, while those on the street craned their necks and clutched cameras as they awaited the chance to say goodbye to the monarch.
The procession of seven groups, each with a military band, travelled via Parliament Square, Whitehall, Horse Guards Parade, The Mall, past Buckingham Palace and Constitution Hill to Wellington Arch at Hyde Park Corner.
While 1,000 armed forces from the UK and Commonwealth lined the mile-long route, British Legion standard bearers flanked the Cenotaph, King’s Life Guards turned out on Horse Guards Parade and King’s Guard saluted the coffin near the Palace.
The King’s Troop Royal Horse Artillery fired minute guns in Hyde Park and Big Ben tolled during the procession.
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At Wellington Arch, the bearer party lifted the Queen’s coffin from the State Gun Carriage into the glass-backed State Hearse, which Her Majesty helped design.
Bands of the Scots and Grenadier Guards played a medley of the Queen’s favourites, including Jerusalem and I Vow To Thee My Country as the coffin arrives.
As the hearse left the monument for Windsor, the parade gave a Royal Salute, led by the King, and National Anthem played out.
The King, the Queen Consort, the Prince and Princess of Wales, along with other Royal Family members, then left for Windsor by car, travelling along the M4.
Thousands of mourners have lined the A4, A30 and A308 to see the State Hearse as it makes the 25-mile journey.
It will arrive at Windsor Great Park through Shaw Farm Gate on Albert Road and on to Long Walk, where tens of thousands of people will bid a final farewell to the Queen.
At the head of the procession, the hearse will travel up Long Walk, through Cambridge Gate and George IV Gate to the Quadrangle.
It will then make its way to St George’s Chapel, where a televised committal service will take place in St George’s Chapel at 4pm.