For those of us who believed that hell would freeze over before the Duke of Sussex was welcomed back into the bosom of his family, it will have come as a surprise when it was revealed that Prince Harry would be telephoning King Charles on his 75th birthday this week.

It has been reported that the call went well: over the course of a warm conversation, during which Meghan also spoke to her father-in-law, plans were set in motion for more regular chats between the two. Another call has reportedly been scheduled for next week. It was also briefed that the King was sent a video of his grandchildren Lilibet and Archie singing happy birthday – as Charles has barely met Lilibet, this was a particularly well-judged touch.

The move on Harry’s part to reconcile with his father might seem surprising after his actions of the past year and the fact that the two had not spoken for months, but one tenet of the royal family has been that even its most disreputable members are brought back into the fold. The Duke of Windsor, perhaps the most notorious royal of the past century, may have been exiled to the Bahamas during the second world war but following its end, he resumed a fraternal relationship with George VI. He also continued to pop up throughout the Queen’s reign, albeit being tolerated rather than welcomed.

Certainly, Harry – who has often been compared to his great-great uncle – shows no interest in returning to Britain and resuming his place as a working royal. But this bridge-building with the King indicates that, one day, he may be a similar presence at state events.

The question remains, however, whether William will be happy to stand next to him, or if the bad relationship between the two brothers cannot now be healed. The tawdry stories in Harry’s memoir Spare about a physical fight between the two of them were deeply embarrassing for the Prince of Wales, a more private man than his father.

The well-informed journalist Omid Scobie – something of a conduit between Camp Sussex and the wider world – has suggested in his new book Endgame that relations between the two have deteriorated to a point that there is ‘no going back’. He has claimed that William’s view was that Harry was a ‘defector’. As Scobie writes, ‘In the eyes of some within the institution, Harry is a threat to the crown. His freedom to exert his own thinking outside of the confines of the institution has made him the enemy.’

The idea of a renegade member of ‘the Firm’ is a frightening one. So it is little wonder that Charles and those around him are doing everything they can – apparently with some success – to bring Harry back into the fold. It would not be surprising if, at some point next year, there are briefings that William and Harry have reconciled and that there has been a peace summit of some kind between the two families. Yet if this does not happen – or if it is purely for a PR show – then Harry should be nervous about what is likely to happen to him after Charles dies and William becomes king.

The Duke’s actions over the past few years, whether he was coerced into them or conducted them of his own free will, have done serious damage to the House of Windsor. His father, judging by his current actions, may be prepared to forgive him, but it is considerably less likely that his brother will. That may, in the end, prove the final undoing for this most troublesome prince.