Lockdown restrictions prevented the celebration from taking place in 2020 in its regular form. Uncertainty about the situation this year meant officials decided to call it off again.
It has only been cancelled once before during the Queen’s reign – in 1955 during a national rail strike.
Each June, the royal family take part in a carriage procession, watching the military parade on Horse Guards Parade and gathering on the Buckingham Palace balcony to enjoy a celebratory flypast.
It marks the monarch’s official birthday and has done since 1748.
The display of pomp and pageantry usually attracts thousands of tourists who flock to central London to see the traditional spectacle.
More than 1,400 soldiers, 400 musicians and 200 horses usually take part in the traditional display.
The troops participating in the march past are drawn of fully trained, operational troops from the Household Division.
The streets are lined with crowds waving flags as the parade moves from Buckingham Palace and down The Mall to Horse Guards Parade.
The Queen is greeted on Horse Guards with a royal salute and carries out an inspection of the troops.
The Queen’s Colour of a battalion of Foot Guards is ‘trooped’ – carried along the ranks – before the sovereign.
Only one colour can be trooped at a time, and the five Household Regiments – Grenadier, Coldstream, Scots, Irish and Welsh Guards take their turn each year.
Other members of the royal family usually ride as part of the parade including the Prince of Wales, the Princess Royal, the Duke of Cambridge and the Duke of Kent in their role as royal colonels, as well as previously the Duke of Edinburgh.
The event has seen some memorable occasions.
When she was five, Princess Elizabeth rode in a carriage with her grandmother Queen Mary and mother the Duchess of York on her way to Trooping, and joined them on the balcony afterwards.
She first appeared mounted as Colonel of the Grenadier Guards riding side saddle in 1947 at the first birthday parade to be held after the Second World War.
She took the royal salute in 1951, when she deputised for her ill father.
She became Queen in 1952 and has continued receiving the mark of respect every year except during the strike of 1955.
In 1981, a teenager fired six blank shots in her direction as she made her way along The Mall.
Her horse Burmese was startled, but the Queen managed to regain control and carried on.
The weather has not always been in her favour. In 2001, she was pictured in her carriage holding an umbrella and dressed in a waterproof coat to protect her from the rain.