Image copyright PA Image caption One of the Queen's own horses was on the racecard at Newbury, while she looked on from the royal box

The Queen has celebrated her 91st birthday by taking part in one of her favourite activities - watching the races at Newbury Racecourse.

It was a more modest affair than the national festivities for her 90th birthday last year.

But military salutes were held across the UK to mark the occasion - including a 21-gun salute of tiny cannons fired by children at Windsor Castle.

Birthday wishes for the Queen have come from around the world.

No prize for Queen's horse

The Queen, who reached her 65-year Sapphire Jubilee in February, is Britain's longest-reigning monarch.

Her thoroughbred Maths Prize was running at Newbury, and the Queen was seen sharing a joke in the royal box before her horse lined up with six other runners.

But the monarch, joined by her daughter the Princess Royal, was denied a birthday gift from Maths Prize, as it finished fifth.

Image copyright PA Image caption The Queen spoke to jockey Ryan Moore and racing manager John Warren during her visit to Newbury Racecourse

Image copyright PA Image caption The Princess Royal spent the day at the races with her mother

Last year, more than 900 beacons were lit up across the UK and overseas as part of her 90th birthday celebrations. Crowds lined the streets in Windsor, church services were held in her honour, and the Queen took part in a walkabout at Windsor.

While her 91st was a more private affair, there was a 41-gun salute in Hyde Park and 21-gun salute in Windsor Great Park at midday, ahead of a 62-gun salute at the Tower of London at 13:00 BST.

The event at Windsor - where the Queen is believed to be currently staying - was different to most military salutes however, with children chosen to fire the 1ft (0.3m) cannons.

Image caption Four-year-old Zachary was one of the 21 children to be selected to fire a cannon for the Queen's birthday

Gifts fit for a Queen

While it is not known what the Queen has received for her 91st birthday, she is known to favour practical gifts over more extravagant presents.

Her children have given her items including a casserole dish and apron over the years, while the Duchess of Cambridge made her some chutney for Christmas - following her own grandmother's recipe.

Speaking on BBC Radio 1 on Friday, the Duke of Cambridge admitted it was "quite hard to know what to get" his grandmother "that she hasn't already got".

He said now "the great-grandchildren can make stuff", which "goes down really well", adding that three-year-old George is "very good at arts and craft".

Many of her favourite presents over the years have reflected her love of animals.

When she was four, the Queen's grandfather King George V gave her her first horse, a Shetland pony called Peggy.

And when she was 18, she was given a corgi called Susan, sparking a lifelong affection for the dog breed. She has now owned more than 30 corgis.

There was also a 21-gun royal salute fired from Edinburgh Castle.

Bells pealed at Westminster Abbey to mark the occasion and Irish Guards performed a rendition of Happy Birthday to You outside Buckingham Palace.

Many of the thousands of tourists at the landmark also joined in with the song.

Media playback is unsupported on your device Media caption Irish Guards mark the Queen's 91st birthday

Buckingham Palace tweeted a picture of the monarch as a baby on her christening day, where she is held by her mother Elizabeth, Duchess of York. They also released a picture of the Queen when she was 21 as she received the Freedom of the City of London - the first significant London ceremony she attended unaccompanied.

Clarence House, the Prince of Wales and Duchess of Cornwall's official residence, shared a picture of the Queen and a young Prince Charles from 1952.

Image copyright PA Image caption The Duke and Duchess of York hold their daughter in a photo dated 1 May 1926

Image copyright PA Image caption Buckingham Palace also released a picture of the Queen receiving the Freedom of the City of London

Well-wishers used the hashtag #HappyBirthdayHerMajesty to tweet their own birthday messages.

The Royal Albert Hall said: "Happy birthday to our patron, Queen Elizabeth!" and a Scout group in Bristol tweeted: "#HappyBirthdayHerMajesty... And wish you a prosperous day!"

Image copyright PA Image caption A picture of the Queen with Prince Charles on his fourth birthday was shared by Clarence House

Canadian Prime Minister Justin Trudeau tweeted a birthday message, wishing the Queen "a happy 91st birthday and continued health and happiness in the years to come", while Foreign Secretary Boris Johnson tweeted: "Hip hip hooray for The Queen and MANY CONGRATS to Her Majesty".

Princess Elizabeth Alexandra Mary was born at 2.40am on 21 April 1926, the first child of the then Duke and Duchess of York, at 17 Bruton Street, the Mayfair home of her grandparents, the Earl and Countess of Strathmore.

She also celebrates an "official birthday" which falls on the second Saturday in June. Two days ahead of her official birthday this year, the snap election announced for Thursday 8 June will be the 17th general election of the Queen's reign.

Media playback is unsupported on your device Media caption How the Queen spent her 90th birthday

It will be marked with the Trooping the Colour ceremony in London- with this year's taking place the week later, on 17 June.

The tradition of the monarch having two birthdays dates back to Edward VII, who was born in November but celebrated his birthday in May and June as the weather was better during those months.