Documents published by Companies House today show William and Kate’s foundation is now just called ‘The Royal Foundation of The Duke and Duchess of Cambridge’.
It follows Harry and Meghan’s decision to move out of Kensington Palace, where William and Kate are based, and set up their own Sussex Royal foundation.
The move will fuel rumours of a fallout of the so-called ‘fab four’, believed to have begun with a row between the two Duchesses and then William and his younger brother.
Royal expert Phil Dampier told MailOnline the split is a ‘massive mistake’, which makes it seem as if the couples are ‘pitting against each other, both personally and professionally’.
Royal sources have denied the feud, saying it is ‘largely about preparing both couples for their future roles, which are obviously on divergent tracks’.
But rows over the Sussexes privacy demands and their jet-setting lifestyle have led to further claims they are growing apart from the Cambridges.
Royal writer Phil Dampier said the charity name change represents the ‘finality’ of their split.
He told MailOnline: ‘It certainly brings it home that they are splitting up.
‘I’ve always thought it was a massive mistake breaking up the Royal Foundation, they were much stronger as the ‘fab four’.
‘It makes it easier to organise, if you have the same office you won’t have diary clashes and things, but also I think they sent a powerful message as a four.
‘Whereas this looks like they’re pitting against each other both personally and professionally.’
He added that he doesn’t believe the recent private jet controversy has helped, saying: ‘It looks like they are scoring points.
‘When Harry said he didn’t want more than two children knowing Kate and William have three.
‘Meghan saying she didn’t want to be on the front of Vogue saying it was boastful, knowing full well Kate has been.’
A new documentary featuring royal expert Ingrid Seward claims William fears Harry and Meghan’s behaviour ‘snubs royal protocol’.
She told the programme: ‘I would think it might bother William a little bit, because he might see the way that Harry and Meghan do things as being detrimental to the business of the monarchy as a whole.’
A fee of £10 was paid to Companies House by William and Kate’s charity to file the ‘Notice of change of name by resolution’, just 14 months after they amended the name to include Meghan when she married into the royal family.
But The Royal Foundation has yet to update the title on its website, which still also features images of the Sussexes.
It still includes pictures of Meghan working on her ‘Together Cookbook’ and Harry’s ‘Endeavour fund’, which supports injured servicemen and women on their road to recovery.
The Royal Foundation website also still includes a section on the ‘Heads Together’ mental health campaign launched by William, Kate and Harry before the Duke of Sussex’s engagement to then-actress Meghan Markle.
Pictures show the two brothers and Kate sprinting along a racetrack with supporters wearing campaign T-shirts cheering them on.
The office for the Sussex Royal charity is based at Buckingham Palace, not Kensington, where Kate and William live.
William, Kate, Harry and Meghan’s joint venture was intended to harness the star power of the four high-profile royals.
They were dubbed the Fab Four after taking to the stage together at the first – and so far only – Royal Foundation forum in London in February 2018.
At the time, Harry said ‘working as family does have its challenges’, but insisted ‘we’re stuck together for the rest of our lives’.
The Sussexes’ plan for their own separate charity was unveiled in June this year, and last week they appointed influential media executive Karen Blackett, chairwoman of MediaCom UK, as their first trustee.
The rumoured rift between the Cambridges and the Sussexes appeared to deepen when Kate and William were pictured taking a £73 flight from Sandringham to Balmoral earlier this month.
William, Kate, George, Charlotte and Louis were pictured boarding the Flybe plane to Scotland almost straight after Harry and Meghan were seen using four private jets in 11 days.
The Sussexes were heavily criticised for their jet-setting ways after Harry said he and his wife only plan to have two children to minimise their carbon footprint.
Supporters claim they would be unable to board a standard plane for security reasons, with Flybe being accused of sending an empty plane for the Cambridges to travel in.
The airline has denied the accusations and Kensington Palace refused to comment.
SOURCE: Daily Mail, Lara Keay