Prince Charles has once again been targeted by a royal expert who raised his serious doubts over the future king's ability to successfully run the affairs of the Firm.
Clive, author of 'The Last Queen' and former newspaper editor, said he looks older than his mother.
Irving told Vanity Fair: "One problem is that he doesn’t look like an invigorating generational shift, does he?
"That’s what would be needed, something that reinvigorates and sends a sense that they’ve understood the modern world."
The author reportedly said Prince Charles presents himself more as the Queen's brother than the son.
Clive Irving has criticised the Prince of Wales, warning that the 70-year-old royal could bring the end of the monarchy.
"He doesn’t like to be challenged, and he thinks like an autocrat. And he’s shown himself to be a hypocrite," the biographer was reported to have said.
Clive also criticised Prince Charles' campaigning to address climate change.
Princess Kate is all set to host Christmas Carol Concert on December 6
Billy Ray clears the air on Miley Cyrus rift with emotional message
Keira Knightley reflects on painful experience of body image issues during younger years
Zayn Malik’s emotional tribute to Liam Payne moves fans to tears
Bowen Yang talks 'SNL', Lorne Michaels, and embracing vulnerability
Queen Camilla hoping to find a 'replacement' as she returns to work and support King Charles
