Paul Burrell said Prince Harry and Meghan Markle should not delay going back to the U.K. and mend their relationship with the royals for the sake of Queen Elizabeth II.

Burrell, who worked as a footman for Her Majesty then as a butler for Princess Diana, said the Duke and Duchess of Sussex's "absence from 'the firm' is more significant than ever." He said members of the royal family have stepped up to help the 95-year-old British monarch amid concerns on her failing health.

Prince William and Kate Middleton have taken in more roles and appeared in several public engagements in the past weeks. Even Prince Edward and his wife Sophie Wessex, and Princess Eugenie represented the monarch at different events. But Prince Harry and Meghan Markle are miles away in America unable to help out because they are no longer with the firm.

"The Queen is an incredibly strong woman and I believe she'll want to work until the end of her life. She always told me that her roles as Queen and a grandmother are the most important things to her. At 95, she's doing great – but she can't do what she used to do. She needs to put her health first and limit her workload," Burrell told Closer magazine.

"We've seen recently that her family have rallied around her to support her and take on more. Kate and William have been thriving – and their work will be a huge support and relief to the Queen. And we've seen other members of the family step up to take on more engagements in recent weeks, too," he added.

The former palace aide said that Prince Harry and Meghan Markle's "betrayal of the royals is more noticeable now than ever" with everyone else in the family "stepping up to support" Queen Elizabeth II. He claimed that the couple "would have been an incredible help" and that the 37-year-old royal "should be here right now, supporting his elderly grandmother."

"I have no doubt Harry and Meghan will have considered the fact she may not have much time left. It's not too late for Harry to return to the UK to support her and be with her," he continued adding, "They must act now to help the Queen, before it's too late and they miss out on precious time with her – but I suspect they won't. I think, years later, they'll realise what they've done, but I can't see it being anytime soon."

Burrell even suggested that Prince Harry and Meghan Markle are being selfish by denying Queen Elizabeth II the chance to see her great-grandaughter Lilibet Diana and denying their children time with her. He said he would "find it unfathomable" if news of the queen's hospital stay did not hit them hard. He said it must have "made them both realise what they've done, how far away they are, and the dilemma they are faced with."

Meghan Markle, Prince Harry, Queen Elizabeth II
"Harry, Meghan and Archie will always be much loved family members," Queen Elizabeth stressed in her statement Photo: POOL / John Stillwell