The Queen - the longest reigning monarch in British history - is about to mark 67 years on the throne.
Princess Elizabeth became Queen on February 6, 1952 on the death of her beloved father George VI.
The monarch is only three years away from her Platinum Jubilee - 70 years on the throne - which would be a first for a British sovereign.
The British government is already planning a Festival of Great Britain and Northern Ireland in 2022 to showcase the UK's strengths and coincide with the jubilee year.
It is not yet known how grand celebrations for the milestone jubilee would be, falling in the year the Queen turns 96.
But the royals were out in force for a weekend of Diamond Jubilee commemorations in 2012 with a Thames river pageant, a Buckingham Palace picnic and pop concert, beacon lighting across the country, a carriage procession and a service of thanksgiving.
The Queen is expected to spend the 67th anniversary of her accession on Wednesday privately at Sandringham, where she has been staying during her annual winter break.
Gun salutes by the King's Troop Royal Horse Artillery in Green Park and the Honourable Artillery Company at the Tower of London will be fired to mark the occasion, as is tradition.
Princess Elizabeth was just 25 and in Kenya on a Commonwealth tour when George VI died in his sleep after suffering lung cancer.
The Queen's coronation took place 16 months later at Westminster Abbey in June 1953.
