Thousands of cheering supporters took to the streets of London on Saturday for the annual Trooping the Colour celebration, where Queen Elizabeth II was honoured for her 90th birthday.

The Queen wore a bright, lime green-coloured coat and hat, as she waved to the crowds from a horse-drawn carriage. She was accompanied by Prince Philip.

And while millions watched the procession on television, Royal biographer Christopher Warwick said only those present were able to experience the full energy of the crowd.

“When you’re here, there is such an amazing atmosphere. Inevitably, the energy is almost palpable,” he told CTV News Channel on Saturday. “(The Queen) is regarded almost, I think, with a fond reverence and that was certainly evident today.”

Trooping the Colour

After parading down The Mall, the Queen joined other royals on the balcony at Buckingham Palace for a fly-past by the Royal Air Force, marking the end of the Trooping the Colour event. Prince William, Kate, the Duchess of Cambridge, their children George and Charlotte, and Prince Harry were among those to take in the display.

The celebration, also known as the Queen’s Birthday Parade, is a royal tradition dating back to the 18th century. King Edward VII became the first monarch to attend the celebrations in person.

CTV royal commentator Richard Berthelsen said the size and enthusiasm of the crowd made this celebration particularly special.

“I think people clearly turned out in large numbers because of the historic nature of this occasion marking, as it does, the 90th birthday of the Queen,” he said on CTV News Channel. “This weekend really is the opportunity for the public to mark the Queen’s birthday and to mark the Queen’s life in a way that they may not have the chance to do in the future.

Britain's Queen Elizabeth II and Prince Philip

“The 90th birthday has been expanded in a way that none of the Queen’s previous birthdays ever were marked…and it’s because I think there’s a sense that this could be the last major celebration of the Queen’s life and her work,” he said.

Despite their age, the Queen and Prince Phillip are already set to celebrate their 70th wedding anniversary next year, Berthelsen said.

Throughout the event, the Royal Family Twitter account shared photos and videos showing members of the family as they took part in the procession.