The Queen reportedly made a final attempt to reconcile King Charles with his youngest son in her final days despite her worsening health.
Prince Harry is said to have "bombarded" his grandmother after his father stopped taking his phone calls, allegedly saying he was "not a bank".
The family drama unfolded after the late Queen stepped back from day to day royal duties following the death of her husband Phillip, meaning that Charles would take on greater royal responsibilities.
Harry is said to have approached his father for money, with Charles saying that he should put in any financial requests through his PA.
The Queen stepped up once again and tried to broker peace between her son and grandson, but when she asked the future king why he wasn't taking Harry's calls, he is said to have replied: "Because I am not a bank."
The split between the Sussexes and the rest of the Royal Family deepened following the announcement of Harry's book deal, fearing they would make it into print.
Harry's high anticipated book, provocatively titled "Spare", will be released in the new year and has already been the subject of heated debate.
An insider revealed to The Sun : “Charles insisted that his son must email him instead.
"Members of the family, including William, had stopped speaking to Harry when they learned of his book deal, fearing what they said could end up in print.
“Harry is not as well off as people are led to believe. He was wanting money."
Nonetheless, a spokesperson for Charles has since claimed that Harry and Meghan are financially independent.
The Sussexes are facing mounting financial pressure, particularly since they have been forced to employ private security firms since withdrawing as working royals.
This comes despite former head of counter terrorism Neil Basu telling Channel 4 News that Harry and Meghan had faced " disgusting and very real" threats from far right extremists.
A preview for the pair's new Netflix documentary has also caused further disturbance in the Royal Family, with critics even suggesting that the preview had been timed to coincide with Prince William and Kate Middleton's visit to the United States.
