Video report by ITV News UK Editor Paul Brand
Gun salutes marking the death of the Duke of Edinburgh have taken place across the UK, in Gibraltar and at sea. Saluting batteries fired 41 rounds at one round every minute starting at midday in cities including London, Edinburgh, Cardiff and Belfast, as well as Gibraltar and from Royal Navy warships, the Ministry of Defence (MoD) said.
Gun salutes have been fired to mark significant national events since as early as at least the 18th century.
They were used to mark the deaths of Queen Victoria in 1901 and Winston Churchill in 1965.
The public was encouraged to observe the gun salutes from home.
The Honourable Artillery Company fired a salute at the Tower of London alongside the 104th Regiment Royal Artillery at Cardiff Castle, and the 105th Regiment Royal Artillery at Hillsborough Castle, Belfast and the Edinburgh Castle.
Watch the gun salutes taking place across the country
Prince Philip passed away at Windsor Castle on Friday, Buckingham Palace announced shortly after midday.
His son, the Earl of Wessex, was seen arriving at Windsor Castle following the death of his father on Saturday morning and left with his wife Sophie around an hour later.
As she left Windsor Castle, the Countess of Wessex said “the Queen has been amazing”. Sophie spoke to reporters from a Land Rover driven by her husband.
Watch Prince Edward and his wife Sophie leaving Windsor
Edward's brother, Andrew, was also seen leaving Windsor shortly after.
The Royal Family's Instagram account shared a moving quote made by the Queen during the celebration of their golden wedding anniversary in 1997.
She said: "He (Philip) has, quite simply, been my strength and stay all these years, and I, and his whole family, and this and many other countries, owe him a debt greater than he would ever claim, or we shall ever know.”
Also on Saturday, the organisers of the Bafta ceremonies announced Bafta President Prince William would no longer be giving a speech as planned following the death of his grandfather.
Prince Philip was the longest-serving consort in British history and dedicated decades of his life to royal duty, serving the nation at the monarch’s side.
Buckingham Palace said in a statement on Friday: "It is with deep sorrow that Her Majesty the Queen announces the death of her beloved husband, His Royal Highness the Prince Philip, Duke of Edinburgh.
"His Royal Highness passed away peacefully this morning at Windsor Castle.
Neil Connery discusses the latest at Windsor Castle
"Further announcements will be made in due course. The Royal Family join with people around the world in mourning his loss."
The Duke of Edinburgh’s children paid tribute to him, describing him as the rock in the Queen and their family’s lives.
It is understood Prince Charles travelled to visit the Queen on Friday afternoon, travelling from his home in Gloucestershire to be by his mother's side at Windsor Castle.
ITV Correspondents discuss the gun salutes up and down the country
Prince Harry and Meghan paid tribute to Philip on the website of their foundation Archewell, replacing its homepage with a memorial site and the words: "In loving memory of His Royal Highness The Duke of Edinburgh 1921-2021.
"Thank you for your service…You will be greatly missed."
ITV News Royal Editor Chris Ship revealed Prince Harry is expected to travel from his home in America back to the UK to attend his grandfather's funeral.
The Princess Royal and the Earl of Wessex reflected on their loving relationship with their father and the nation's longest serving consort.
Princess Anne speaks to ITV News Royal Editor Chris Ship about her father, the Duke of Edinburgh
Paying tribute to His Royal Highness, they shared their personal childhood memories of the Duke and the Queen, the famed Duke of Edinburgh Award and their father's lasting legacy.
The Prince of Wales said that while his father did not "suffer fools gladly", he was good at showing him how to do things.
Charles added: "Well you know he didn’t suffer fools gladly, so if you said anything that was in any way ambiguous he’d say ‘make up your mind’.
"So perhaps it made one choose your words carefully.
"He was very good at showing you how to do things and would instruct you in various things."
The Duke of York said Philip used to read to the family in the evenings.
Andrew added: "Like any family of the day your parents went out to work during the day, but in the evening just the same as any other family we would get together, we would sit on the sofa as a group and he would read to us."
First Sea Lord and Chief of the Naval Staff Admiral Sir Tony Radakin, the most senior officer in the Royal Navy, also paid tribute to Philip. In a statement released on Saturday morning, he said: "His genuine empathy, affection and engagement with the Royal Navy resonated with us all.
"His generous spirit, his delight in all aspects of the Naval Service, and his deep understanding of our values, standards and ethos made him such a close friend to the Service for over eight decades." In London, the King’s Troop Royal Horse Artillery will ride out from their base at Napier Lines, Woolwich Barracks, onto the Parade Ground. There will be 71 horses, 36 of them pulling six 13-pounder field guns dating from the First World War. The same guns were also fired for Philip’s wedding to the Queen in 1947 and at her Coronation six years later in 1953.
Watch: The remarkable life of the longest-serving royal consort in British history
There will be no lying in state and no state funeral for Philip, in accordance with his wishes, but Covid-19 means even more traditions will not be followed.
People have also been urged not to gather at Buckingham Palace, Windsor Castle or any other royal residence, in order to stick with coronavirus regulations.
The Royal Family has asked members of the public consider making a donation to a charity instead of leaving floral tributes in memory of the Duke of Edinburgh.
An online Book of Condolence for those who wish to leave messages is available on the Royal website (www.royal.uk).
Philip's ceremonial royal funeral and burial are expected to take place in St George’s Chapel at Windsor Castle - though formal details are yet to be confirmed.
Ships taking part include the HMS Diamond, HMS Montrose and HMNB Portsmouth, while the Royal Gibraltar Regiment will join the salute from the British overseas territory.
Philip joined the Royal Navy after leaving school, beginning at the Britannia Royal Naval College in Dartmouth in May 1939, and was singled out as best cadet.
During the Second World War, he served on several ships – firstly on HMS Ramillies – and saw active service against German, Italian and Japanese forces.
In March 1941, he was a searchlight control officer on the battleship HMS Valiant and was mentioned in despatches for his part in the battle of Matapan against the Italian fleet.
Shortly afterwards, he was awarded the Greek War Cross of Valour.
He rose rapidly through the ranks, earning promotion after promotion, with some believing he could have become First Sea Lord – the professional head of the Royal Navy.
But the Duke stepped down from his active role in the forces to fulfil his duty as the Queen’s consort.
In recognition of his long-standing connection with the Royal Navy, the Queen conferred the title of Lord High Admiral on the Duke to mark his 90th birthday in June 2011.