Queen Elizabeth II kicks off historic jubilee celebrations

Queen Elizabeth II on Thursday kicked off the first of four days of celebrations marking her record-breaking 70 years on the throne, to cheering crowds of tens of thousands of people.

But the 96-year-old sovereign's appearance at the Platinum Jubilee -- a milestone never previously reached by a British monarch -- took its toll, forcing her to pull out of a planned church service on Friday.

"The queen greatly enjoyed today's birthday parade and flypast but did experience some discomfort," Buckingham Palace said.

"Taking into account the journey and activity required to participate in tomorrow's national service of thanksgiving at St Paul's Cathedral, Her Majesty with great reluctance has concluded that she will not attend."

The extent of the queen's participation in the historic jubilee had already been in doubt due to her difficulties walking and standing, and a recent bout of Covid.

But dressed in dove blue, her hands clasped on a walking stick, she appeared on the Buckingham Palace balcony to take a salute after the centuries-old Trooping the Colour military parade.

After gun salutes and a fly-past of military aircraft, she made a second appearance on the balcony with three generations of her heirs, princes Charles, William and George, and other close family members.

But many acknowledged the coming end of an era in what some feel could be the last major public event of her long reign.