A loud shout of “God save the King” erupted as the couple arrived and Charles began warmly greeting the waiting masses.
The new monarch and his wife took off about 12.30pm on Friday (9.30pm AEST) from Aberdeen International Airport in Scotland, where they had travelled to be with the Queen at her Balmoral home before her death.
The King will today hold his first meeting with Prime Minister Liz Truss.
Tomorrow he will be officially declared King by the UK’s Privy Council, although he already assumed that title immediately upon his mother’s death.
As per tradition dating back to the 15th century, the Garter King of Arms, who is responsible for governing royal heraldry in England, Wales and Northern Ireland, will step out onto the balcony at St James’s Palace and officially proclaim Charles as the new King.
A 41-gun salute at London’s Hyde Park will follow.
Charles is due to address the UK at 6pm tonight (3am AEST).
St Paul’s Cathedral in London will hold an evening service to mark the Queen’s death at 6pm local time, which will be open to the public. Members of the royal family will not attend.
In the days that follow, the new King will attend a joint session involving both houses of the British Parliament and embark on a tour of the UK, visiting Scotland, Northern Ireland and Wales.