A total of 200 to 250 leaders and their spouses attended the funeral service at Westminster Abbey, including delegations from the US, China, Europe and dozens of Commonwealth countries.
Members of royal families from across the world – led by Denmark's Queen Margrethe II of Denmark, third cousin of the Queen and now the only female monarch on the throne – were also present.
Notable by their absence were six countries which were not invited – Russia, Belarus, Myanmar, Afghanistan, Syria and Venezuela.
African leaders were among the first to enter the abbey, with Sudan's military leader Abdel Fattah al-Burhan crossing the cordon, followed by delegations from Malawi and Nigeria.
Brazil's president Jair Bolsonaro was seen arriving with his wife Michelle, as was Israeli president Isaac Herzog. Italian president Sergio Mattarella was among the last to arrive, travelling in a chauffeur-driven Maserati with the number plate ITA 1.
The dignitaries were among more than 2,000 people who attended the first state funeral in the UK since prime minister Winston Churchill was laid to rest in 1965.
Mr Biden’s official vehicle, known as “the Beast”, was stuck in traffic outside of a Pret a Manger coffee shop near Marble Arch on the way to Westminster Abbey. He was one of a number of leaders who made their own way to the service, despite attempts by the UK Government to restrict traffic by asking dignitaries to share transport.
Government documents published last week had revealed world leaders would be transported to the funeral en-masse – on a bus, rather than taking their own private transport. Heads of state, prime ministers and ambassadors from across the world, including French president Emmanuel Macron and Canadian Prime Minister Justin Trudeau, travelled to the Royal Hospital Chelsea amid tight security, then boarded coaches transporting them two miles to the service at Westminster Abbey.
However, a spokesperson for Prime Minister Liz Truss stressed the “arrangements for different leaders will vary”.
Mr Biden’s 18-foot custom-made Cadillac has reinforced 8-inch steel walls and defensive weapons.
Mr Trudeau said he welcomed the bus transport as a chance for impromptu diplomacy.
"Increasingly in various summits there is a need to travel on buses and there is actually a lot of work that gets done," he said.
German president Frank-Walter Steinmeier described the funeral as a “once-in-a-century event”.
“People were used to rallying behind this Queen for over 70 years, and now everyone has the sense that something is missing, not only in Britain and in London, but worldwide,” Mr Steinmeier told German media.
Chinese vice-president Wang Qishan represented Beijing at the funeral, amid tensions after its government delegation was blocked from attending the Queen's lying-in-state earlier this week. China's ambassador to the UK had been banned from Parliament as part of sanctions relating to China’s alleged treatment of Uighur Muslims.
Reports claimed House of Commons Speaker Sir Lindsay Hoyle had told colleagues he declined a request for Chinese officials to be allowed to access Westminster Hall. The Chinese delegation arrived at the funeral wearing white face masks bearing the Chinese flag, in a motorcade that was several vehicles long.
Japan's Emperor Naruhito and Empress Masako left the country for the first time since the pandemic to attend the funeral. The decision to attend is an unusual one for the emperor, who traditionally stays away from funerals outside of close family members because of cultural belief in the Shinto religions that considers death impure.
As well as the delay faced by Mr Biden, who was seen wearing sunglasses in the back of his car as it waited in traffic, the vehicle carrying the Emir of Qatar, the only vehicle flying its national flag from its bonnet, was forced to wait in front of television cameras for 20 minutes at the checkpoint while police officers spoke back and forth on their radios. Eventually it was allowed to enter.
Joe Armitage, a 27-year-old political consultant, filmed the moment that Mr Biden’s car was delayed outside the coffee shop. He said members of the public attempted to approach the car when it stopped, but were halted by police.
"Everybody was aghast when the massive motorcade with half a dozen outriders came to a complete stop and the president of the United States came into view, just a metre away," Mr Armitage, from London, said. "People attempted to walk up to his window, but were quickly ordered away."
Moroccan Crown Prince Moulay Hassan, 19, attended the service to represent his father, King Mohammed VI, while Queen Margrethe II, who is now Europe’s longest reigning monarch, and King Felipe and Queen Letizia of Spain waved at crowds as their convoys arrived.
Olena Zelenska, wife of Ukraine's president Volodymyr Zelensky, represented Ukraine at the funeral, after visiting the Queen’s coffin in Westminster Abbey on Sunday.
She said it was a "great honour" to be present at the Queen's funeral "on behalf of all Ukrainians".
Mrs Zelenska, who met the Princess of Wales at Buckingham Palace yesterday, said the Queen's attention to Ukraine "was an important signal of support".
"She wished us better times and shared our desire for freedom – we will always remember it with deep gratitude," she wrote on Twitter.
However, Russian president Vladimir Putin and Belarusian president Alexander Lukashenko were not asked to attend due to the invasion of Ukraine. A Kremlin official described the snub as "profoundly immoral" and "blasphemous".
Mr Putin paid tribute to the Queen on the day of her death, saying the late monarch “rightfully enjoyed the love and respect of her subjects, as well as authority on the world stage”.
Thai media claimed the King of Thailand, King Vajiralongkorn, had not been invited to the funeral. However, it is understood an invitation was extended, but the UK’s ambassador to Thailand was due to attend in his place.
Myanmar was also not invited due to the military coup in 2021, while North Korea, Iran and Nicaragua were invited to send ambassadors, but representatives from Syria, Venezuela, and Afghanistan were not invited.