All eyes were on the Royal Family as they watched, united on the balcony of Buckingham Palace, a historic flypast to mark a century of the Royal Air Force.

The Queen led a day of national celebrations on July 10, 2018, which saw 100 aeroplanes, one for each year of the RAF, glide over the iconic balcony.

Earlier, more than 2,200 people attended a Westminster Abbey service, including the then prime minister Theresa May, secretary of state for defence Gavin Williamson and Labour leader Jeremy Corbyn.

After the service, the family met veterans, personnel, charity representatives and members of the civil service.

And, while all seemed smooth-sailing on the surface, looking back to that day, eagle-eyed royal observers have noticed a potential early sign that not all was well between Meghan and Kate at the Westminster service.

As Kate, with Meghan behind her, greets the Dean of Westminster, The Very Reverend Dr John Hall, Prince William steps in between them.

Body language expert Judi James told MailOnline: ‘Superficially, and with the benefit of hindsight, now that we know about the tricky relationship between Meghan and Kate, this looks very much like a devoted and protective husband strategically and very pointedly stepping between his wife and her nemesis in the form of a human shield.

‘William’s body language shows he is clearly aware that Harry and Meghan have honed into position behind him and he immediately ducks his head to move to stand next to his wife, even sucking his lips inward in what is often a signal of regret.’