Plans are being drawn up so the Queen and attend the memorial service for her late husband Prince Philip later this month, it has been reported.
It comes after Buckingham Palace said her Her Majesty will not be attending the Commonwealth Day service on Monday and that her son Prince Charles going in her place instead.
It is understood the Queen "still hopes" to attend the Service of Thanksgiving for the Duke of Edinburgh on March 29 at Westminster Abbey, but there are concerns she may not be mobile enough to do so.
The 95-year-old monarch has reportedly ruled out using a wheelchair at this stage.
The Mail on Sunday understands she has ruled out the option of using a wheelchair at this stage and remains determined to continue to walk for as long as possible.
It is being reported that her aides said the Queen was so frail she is unable to even walk her beloved corgis.
Queen Elizabeth II has owned more than 30 corgis in her lifetime but she has not taken her dogs for a walk at Windsor Castle for six months.
The Queen, who turns 96 next month and has recently recovered from Covid, was last week moving around Windsor Castle without a walking stick and is not suffering from a new illness.
But she still made the “regretful” decision late on Friday to pull out of the annual Commonwealth Service, which is usually a highlight in her calendar.
In a statement, the palace said: “The Queen has asked The Prince of Wales to represent Her Majesty at the Commonwealth Service at Westminster Abbey on Monday.”
It is understood that detailed plans are being drawn up to find a way for the Queen to comfortably attend the service for Philip.
The service has already been cut down to 50 minutes and to have the Queen use a side door so she doesn't need to do the long walk to the aisle to get to her seat, it has been reported.
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Penny Junor, a royal biographer, said told The Mail On Sunday : "The Queen is extraordinary. She has gone on with great vigour for years but we have to remember she is 95 and not superhuman.
"In other respects, she is on great form. The Queen is fantastic on Zoom calls, but I think events where she is required to walk or go up any steps are not going to be feasible any more.
"And fortunately we have the technology that means she is not going to disappear from view altogether."
Last month, she acknowledged her frail condition for the first time during a royal engagement at Windsor Castle.
The Queen told visiting military officials: “As you can see, I can’t move.”
She last met a group of people in public on February 5.