Royal insiders at palace have made startling revelations about Meghan Markle and Prince Harry as the duke marks his 40th birthday.

The sources at palace informed the Daily Mail, per OK! Magazine that Archie and Lilibet doting parents see conspiracy "at every turn" and make everything "hard work."

They also labelled Meghan and Harry 'exhaustingly difficult.'

The insider who is alleged to have experienced the crisis claimed that Harry "wasn't happy" and it was evident, suggesting that his departure from the UK was the right move for the the California-based royal couple.

Harry "needed to make a break" from what was termed "a horrible, toxic atmosphere", the source explained as the duke celebrates his 40th birthday with Meghan and their children in California.

The fresh claims came as Prince Harry received sweet birthday wishes from royal family on his milestone birthday.

“Wishing The Duke of Sussex a very happy 40th birthday today!”, the palace tweeted King Charles birthday message for Prince Harry.