The Queen will not attend the Epsom Derby on Saturday as planned, Buckingham Palace has confirmed.
However, the monarch is expected to watch the sporting event on TV from Windsor Castle.
It is expected that the Queen’s daughter, the Princess Royal, will attend and represent her mother.
The announcement comes after the monarch pulled out of the Service of Thanksgiving held on Friday as part of her platinum jubilee celebrations.
In a statement, Buckingham Palace said the Queen “greatly enjoyed” her birthday parade and flypast in London on Thursday as part of the Trooping the Colour Parade but “did experience some discomfort”.
The palace continued: “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 Queen is looking forward to participating in tonight’s beacon lighting event at Windsor Castle, and would like to thank all those who made today such a memorable occasion.”
It is believed that the Queen experienced episodic mobility issues during the daytime events.
On Friday, she watched the Servive of Thanksgiving on TV in Windsor.
The majority of the Queen’s public appearances so far this year have been online.
However, she recently appeared at the Chelsea Flower Show in person in an electric buggy.
According to PA, the Duchess of Cambridge told an attendee at a Guildhall reception on Friday that the Queen had a “lovely” time at Thursday’s Platinum Jubilee celebrations but found the day “very tiring”.