This comes as Charles is set to stand in for the Queen, alongside his son Prince William, at the State Opening of Parliament tomorrow.
In what is seen as an unprecedented move, the Queen has delegated certain powers as head of state to the two royals as Counsellors of State, in order to allow them to open Parliament on her behalf.
Mr Hunt said it is a “significant moment for two future kings” as it allows Prince Charles to “accelerate” his training.
A spokesperson for Buckingham Palace confirmed the Queen would “reluctantly” be pulling out of the event after consultation with her doctors.
Prince Charles will read The Queen’s speech on her behalf and Prince William will be in attendance for his debut State Opening appearance.
The Queen’s throne will remain empty in the House of Lords, while the Prince of Wales and the Duchess of Cornwall will sit in their usual seats.
The Buckingham Palace spokesperson said: “The Queen continues to experience episodic mobility problems, and in consultation with her doctors has reluctantly decided that she will not attend the State Opening of Parliament tomorrow.
Speaking to the PA news agency, Mr Hunt said: “This is a significant moment for two future kings.
“Charles will accelerate his on-the-job training.
“The heir is teetering on the edge of becoming a de facto prince regent.
“William will observe what awaits him.
“With the Queen progressively withdrawing from public life, the palace is keen to show the monarchy is safe in the hands of father and son.”
Speaking about Prince Charles’ increased role, constitutional expert Dr Bob Morris said it is “more likely than not” that the arrangements would continue for future state openings.
The expert, of UCL’s Constitution Unit, continued: “It is unprecedented and it’s the way in which the constitution flexes to accommodate unusual circumstances.
“I can’t think of any possible earlier version of this.”
He added: “They’ve gone down the Counsellor of State route, that’s one way round it.
“The Prince of Wales is giving the speech and William is there as his stay and support as it were.
“It’s a rather odd confection but it works.”
Source: EXPRESS CO UK