There’s no doubt about it: Andrew Mountbatten Windsor has successfully lobbed a custard pie in the face of the police and judicial system. Holed up in his humble Sandringham abode, he will be rubbing his hands with glee that a rare bit of good news has come his way. The former prince is not a drinking man, but the close coterie of chums in Norfolk who have not shunned him since his fall from grace will undoubtedly be raising a glass for their beleaguered friend.

It all turns on something of a technicality. Thames Valley Police has accepted that the search warrants used to take possession of material from his homes in Sandringham and Windsor were unlawful.

Mountbatten-Windsor clearly employed some pretty savvy lawyers to pick a hole in the police procedure, and it is a major embarrassment for the force. However, Mountbatten-Windsor should not be cheering too loudly, because the judge spelt out that the fact that the search warrants have been quashed does not mean that the whole of the investigation is unlawful. Nor does it bring the inquiry to an end.

The police are now involved in legal proceedings to decide how the material seized will be managed and whether they can lawfully retain it to support their ongoing investigation.

Mountbatten-Windsor has always denied any wrongdoing. But ever since his shock arrest on his 66th birthday eight months ago, the police have been trying to build a case to support allegations of misconduct in public office by the former prince when he was a UK trade envoy. It was alleged that he shared confidential and sensitive information with the convicted child sex offender, Jeffrey Epstein. The lengthy investigation has left him in limbo, unsure of his future. But now he is reported to be feeling buoyant after beginning his fight back.

For the King, however, the High Court’s decision signals yet another unwelcome onslaught of negative publicity about a member of his family. Not that he is believed to be in contact with Mountbatten-Windsor; in fact, it was made absolutely clear by Buckingham Palace that King Charles would not countenance his brother using any of the money he gives him to fight his legal battle. And that is Palace parlance for saying that the King is hopping mad that his brother would brazenly challenge His Majesty’s judicial system.

Mountbatten-Windsor has certainly won this particular skirmish. But it could possibly just extend his time in limbo as the police compile their case to be allowed to keep the documents they seized.

In the end, surely the only way for Mountbatten-Windsor to clear his name – and it’s important to remember that at this stage he has not been charged with anything – is to do just that: clear his name. To achieve that, surely the best course of action would be to cooperate fully with every inquiry involving the dealings of the convicted paedophile, Epstein? As yet, however, there is absolutely no indication that Mountbatten-Windsor has any intention of doing so.