Charles made a surprise 200-mile-round-trip to see his father last weekend during the Duke of Edinburgh’s prolonged stay in hospital as he suffers from an infection.

Former Buckingham Palace-insider Dickie Arbiter has speculated the visit would have been at Philip’s request.

Mr Arbiter, who worked for the Queen as a press officer between 1988 and 2000, told True Royalty TV’s weekly The Royal Beat programme the duke was likely to have been ‘planning for the future.’

He said: ‘I think it was at the request of the duke that the Prince of Wales visited.

‘To lay the ground. Look the man is 99, he is in with an infection. My guess is that he will come out, he will walk out and he will go back to Windsor.

‘But eventually he is going to die and he was just saying to Charles, “one day you are going to be the leading man of the family”.’

Charles’ visit came in the midst of another royal crisis as the Queen stripped Prince Harry and Meghan Markle of their Royal patronages following the couple’s decision to leave their roles as senior royals and move to the US.

Police officers have been guarding the entrance to the King Edward VII hospital for the duration of the Duke of Edinburgh’s stay

Charles was pictured looking teary-eyed as he left the hospital last week

Prince Philip’s 12 day stay is the longest amount of time he has spent in hospital ever

The heir to the throne was pictured leaving the site looking teary-eyed after a visit that only lasted around half an hour last Saturday. He drove straight back to his home at Highgrove House in Gloucestershire.

There had been speculation that Philip asked Charles to visit to brief him on the situation.

No other royals have visited the Duke in the London hospital during his 12-day-stay, although Prince Edward has spoken to him over the phone.

Some criticised the actions of Charles who visited during the pandemic when many have not been able to see their relatives. The hospital had stressed visits would only allowed in exceptional circumstances.

Yesterday palace sources confirmed the 99-year-old would spend another weekend in hospital, the longest stint the duke has spent in hospital ever.

Buckingham Palace has not provided an update on his condition since Tuesday when it was said he was ‘comfortable’ and ‘responding well to treatment.’