No one knows more about the shortcomings of Prince Andrew than Andrew Lownie, an English historian who wrote the recently released Entitled: the Rise and Fall of the House of York. I spoke to him a number of times this week.

Fitz: Mr Lownie, there have been so many appalling revelations about Andrew in the past couple of weeks, I thought it timely to go straight to the man whose book comprehensively documents his descent – you. Are you personally shocked by the latest revelations, or did you know them all anyway?

AL: I am not shocked. I had a lot of the material that has emerged but couldn’t put in my book for legal reasons, or I couldn’t properly double-source them. As to the posthumous Virginia Giuffre book, her ghostwriter Amy Wallace is a reputable journalist who did due diligence. So I believe those revelations, but they don’t surprise me. And I think there’s lots more still to come, lots more, and it will be even more damaging material.

Fitz: What could be worse than the current allegations of orchestrating a smear campaign against Giuffre, having an orgy with eight girls, consorting with Chinese spies, and telling Epstein he looks forward to “playing again with him soon”, all of which – we should note – are only allegations, and nothing has been proven.

AL: I think the area that hasn’t really come out is the national security elements. A lot of this has been pushed by the intelligence services, who are very concerned about the way the royal family has been penetrated by foreign intelligence services.

Fitz: You will know well the line of the famed 19th-century English constitutionalist Walter Bagehot, who, referring to the monarchy, suggested that “its mystique and authority depend on secrecy and reverence”. You, personally, have pulled the curtain aside, and not just let in daylight but focused searing sunlight through a magnifying glass with such intensity that the acclaimed British historian A.N. Wilson, a monarchist, has said the contents of your book are “the stuff of which revolutions are made. It made me feel I wanted a republic”. Are you a republican, and did that motivate or colour your book?

AL: I am a monarchist, but I’m a slightly more disillusioned monarchist. I’m becoming a hopeful monarchist in that after banging on about the need for accountability and transparency for a decade – and being ignored by everyone – a lot of people are now offering to do things that should have been done long ago. And I come from the position of an honest friend, saying that if this monarchy is to survive, it depends on the trust and respect of the people, and it will only have that trust and respect if people don’t feel that the royals have got their noses in the trough. If they do, that’s the end of the monarchy. And I don’t want that to happen. I mean, I may be helping it happen, but that’s not my intention. My intention is just to bring sunlight into these institutions.

Fitz: Do you accept, nevertheless, that your book completely undercuts the whole monarchist schtick that these are people with blue blood who are inherently better than the rest of us? I mean, the Andrew of your book comes out as a man with a completely corrupted soul, a liar, a shameless grifter on the public purse, an exemplar of the result of a life of unfettered privilege.

AL: Yes, they’re worse than ordinary humans because there’s a sense of entitlement that turns them into monsters. But you’re absolutely right. I mean, we’ve got the problem here in Britain that we got rid of hereditary peers in parliament, and yet we still stick with the hereditary principle with the monarchs. So we are moving, I agree, to a position where it becomes more and more untenable.

Fitz: While writing your own book – which you did over four years, with 300 interviews and endless freedom-of-information requests – when exactly were you most shocked? When did you lean back in the night and say: “I simply cannot believe what this man has done”?

AL: Well, clearly the 40 prostitutes visiting Andrew’s hotel room in four days in Thailand was one, as was the fact that effeminate young men were also brought to him. But I think the most shocking thing is how the palace protected him and enabled him, covering up his crimes. Whenever people went and complained to the Queen, they were sent away with a flea in their ear.

Fitz: The role of the late Queen in this interests me, as while alive it seemed she could do no wrong. But, together with Prince Philip – who you portray as a distracted adulterer – your clear view is she must bear a lot of responsibility for creating this awful man?

AL: Yes, and I think that’s the most shocking revelation, the one that people find most hard to accept. She had a blind spot, while Prince Philip just didn’t deal with him at all. It meant that all the way through his life, he was protected. He was told he was wonderful. Anyone who didn’t say that didn’t progress in their career. So he was over-promoted in the navy, and everyone just indulged him. And he just realised: he could do exactly what he wanted, from when he was five years old to now, 65 years old.

Fitz: You are saying that the Queen was a terrible mother?

AL: I think the Queen has to take some responsibility for the monster she created. To be fair to her, her other three children are not like him, and he’s always been described as the runt of the litter.

Fitz: While the Queen was on the throne, the edifice of the monarchy seemed very, very stable. But since Charles has taken over, the whole thing seems to be wobbling. It was once famously said by an American comedian that “Jimmy Carter as president is like Truman Capote making love to Dolly Parton – the job’s just too big for him”. Is this job, similarly, just too big for Charles? It is obvious that he let the whole Andrew thing just get completely out of hand, and every move he’s made has been too mild and too reactive – a pound short and a month late.

AL: Yes. I think it’s going to overshadow Charles’ very short reign, which will be seen as a transitional reign, and the changes, if they come, will come with William. Charles is born in the 1940s. He’s an old man. He’s been used to the old system. William will change things, have a much more slimmed-down monarchy – just the direct line and get rid of titles for all the hangers on, etc. He will focus more on pastoral care rather than pomp. So I think we will see change, and I think William will come to the throne much sooner than people expect.

Fitz: Because of Charles’ ill health, or because he will stand down for being hopeless?

AL: William will come to the throne because Charles isn’t up to it because of his health problems. We’re already seeing power moving across to William. William is now dealing with the issues and calling the shots. Charles is just working on his legacy. William realises they need to catch up on the story, get ahead of it. He is pushing for Andrew to be stripped of everything, and face the law like an ordinary citizen.

Fitz: OK, the news has just broken that Charles has, in fact, moved [on the artist formerly known as Prince Andrew, and now to be ordinary citizen and a disgraced one at that, Andrew Mountbatten Windsor. And he is at last to be moved out of his royal digs into a private residence.] What do you make of it?

AL: It’s a stop gap.

Fitz: Will it help save the monarchy?

AL: I think it will depend if charges are brought.

Fitz: Meanwhile, the British group Republic is taking private action against Andrew for sexual assault, corruption and misconduct in public office? You must have heard all kinds of allegations against him. Have you heard these ones?

AL: There are grounds to charge him and I believe the due process of law should take place even if that means he goes to prison. The most likely [successful] charge is misconduct in public office, concerning serious wilful abuse or neglect of the power or responsibilities of the public office held.

Fitz: Where do you think that Andrew will be a year from now?

AL: Well, I would hope, actually, that he would be standing trial for misconduct in public office. But I suspect he will be in a country without an extradition treaty with Britain.

Fitz: It’s going to get that bad – that he’ll try and do a runner, get out of Dodge, get out of England and get to a place where he can’t be extradited?

AL: Yes. Everyone has got the bit between their teeth. They’re not going to stop until this guy is really held to account. I mean, people go to prison here for tweeting. You know, there are so many things that he could be charged with, that I think the authorities will have to do something. We already are seeing politicians, who were silent, speaking out, including Conservative Party ones. We’ve got the press in full pursuit of him.

Fitz: Lenin said, “Sometimes there are decades where nothing happens and weeks where decades happen.” Is this one of those weeks, and will the monarchy ultimately survive all this?

AL: [Cutting Andrew obviously helps.] If the public outrage continues to rise it will fall.

Fitz: The hounds have indeed been set loose, no doubt in no small part because of your book on the Yorks – done by a serious historian, not a tabloid hack, which has therefore legitimised serious inquiry into his affairs. You have done the monarchy serious damage. You’re a Cambridge man, a historian, an academic, a figure of the establishment. Do you ever take flak personally in your gentlemen’s clubs for what you have wrought?

AL: Oh, absolutely. My mother-in-law has stopped talking to me. I have people turn their back on me in my clubs. I’m constantly trolled. I have my work denigrated. And I’ve just been told today that Andrew and Fergie have paid a PR firm to discredit me. But I’ve got broad shoulders, and I’ve had worse in my life. It just reflects badly on them.

Fitz: Well, keep up the fine work. Thank you very much, Andrew.

Peter FitzSimons is a columnist and author.