It crashed and landed on its side near the bank of the River Thames at Mapledurham.
HM Celebrates 90th Birthday In Windsor
The event in the grounds of Windsor Castle included displays by famous military and civilian horse troupes from around the world.
The Queen was joined in the royal box by members of her family including the Duke of Edinburgh, the Prince of Wales and Duchess of Cornwall, the Duke and Duchess of Cambridge and Prince Harry.
:: All The Queen's Horses: Her Majesty's Passion
The monarch celebrated her 90th birthday on 21 April, and Prince Charles wished his mother "the happiest of very special birthdays" writing in the official programme to mark the event, the culmination of the annual Royal Windsor Horse Show.
Gary Barlow kicked off the entertainment with a performance of the song Something About This Night.
Actors narrated historic moments from the Queen's life starting with Downton Abbey star Jim Carter who covered the monarch's childhood years and introduced his wife Imelda Staunton who performed a song.
Dame Helen Mirren took the audience through the monarch's war years and how the nation fought against Nazi tyranny.
The actress went on to describe the young Queen's coronation on 2 June 1953 and at the end of the sequence mezzo-soprano Katherine Jenkins gave a rousing rendition of I Vow To Thee My Country.
One of the highlights of the night was a performance by Australian pop queen Kylie Minogue, who sang a version of her song I Believe In You.
As she performed, Jean-Francois Pignon, introduced as the horse whisperer of France, enthralled the spectators with his command of a group of horses including a Shetland pony.
Members of the royal family including the Earl of Wessex, his daughter Lady Louise Windsor and Zara Tindall were among those taking part in the show on horseback.
Other highlights included the intricate and mesmerising percussion display from the Top Secret Drum Corps from Switzerland and the Middle Eastern fantasy of the Royal Cavalry of Oman.
And at one stage members of the Royal Family - including the Duke of Edinburgh and Duchess of Cornwall - covered their ears for a loud gun salute.
A major part of the Queen's life has been her role as head of the Commonwealth - the 53-nation organisation known as "the family of nations".
Billions actor Damian Lewis told the crowds: "One of the key pillars of this celebration is the Commonwealth.
"The Queen's commitment and dedication to it is immense.
"It is a testament to Her Majesty's constant engagement with these nations that she is loved in equal measure by those who have declared independence from the United Kingdom and those to whom the Queen is still head of state."
Military bands from across the Commonwealth performed but the New Zealand Army Band stole this part of the show playing Vangelis' theme from the film Chariots Of Fire, which had the spectators laughing as two of the band ran in slow motion.
The finale saw all the acts - from countries as diverse as Azerbaijan to Fiji - assemble in the main arena for the closing moments when a birthday cake was brought before the crowds.
Dame Shirley Bassey sang the James Bond theme Diamonds Are Forever, before the Happy Birthday song was played, followed by the National Anthem.
(c) Sky News 2016
A vigil will be held in Oxford tonight for the victims and their families after Wednesday's attack in Westminster.
hames Valley Police is reviewing security after yesterday's terror attack in London.
Thames Water is set to be fined for polluting the Thames with 1.4 billion litres of raw sewage.
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