The Queen has a 'mind versus body' attitude and no one but Philip has ever told her to 'stop', one royal expert says.
The monarch, 95, spent Wednesday night in hospital after being admitted for "preliminary investigations".
She was back at Windsor Castle by lunchtime yesterday and is understood to have gone through one of her government red boxes.
But royal commentator Angela Levin says when the Queen was given medical advice to rest and she 'reluctantly' agreed, Prince Philip would have been a voice of reason.
"We see the Queen when she goes out but she is actually working a lot within the Palace because she does Zoom things," Levin says.
"She also has a big red box with loads of paperwork that she has to go through.
"Loads of these things are very taxing and I think she should be encouraged to step back quite a bit now."
"She wants to be very well for the Platinum Jubilee next spring and I think she should relax more," Levin continues.
"I think it is very wrong of people to say that the Queen will still be here in 10 or 20 years because that puts pressure on her and that could make her more active.
"I think it is a sort of mind verses body issue."
TalkRadio host Mike Graham also reflected on what impact Prince Philip would have on the Queen's schedule if he was still alive.
He said: "I do wonder sometimes because Prince Philip is not around anymore to tell her to not go so hard, to slow down.
"Which is something I imagine he would have done, there is no one really telling the Queen that."
Ms Levin agreed and noted it was unlikely anyone else in the Royal Family would do the same.
Ms Levin replied: "Nobody would tell the Queen that, they don't dare to."
The Queen, who was seen using a walking stick during an engagement at Westminster Abbey last week, was said to be disappointed not to be able to travel to Northern Ireland on Wednesday, and reluctantly heeded the advice of her royal physicians.
She is still expected to attend the Cop26 climate conference in Glasgow next month.
Her last overnight stay in hospital was in March 2013, when she was admitted with symptoms of gastroenteritis.
In a statement, a Buckingham Palace spokesman said: "Following medical advice to rest for a few days, the Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today, and remains in good spirits."
A source told the Daily Mail: "Quite understandably, a cautious approach is being taken by the medical team.
"Her Majesty was back at her desk this afternoon and undertaking light duties."
For more royal and lifestyle news, sign up to OK!'s daily newsletter here.
