There is no easy way to ask a senior member of the royal family about their links to a prolific paedophile. There is no easy way to ask a senior member of the royal family if they had sex with a minor. I have been turning these formulations over in my mind on the way to the interview and, believe me, there just isn’t.

I am heading across the courtyard of Buckingham Palace for the third time in as many weeks. I am lugging a huge silver Sweaty Betty bag bursting at the seams with shoes and jackets. It is so large and so bling that it looks as though I’m trying to move in. And I realise, as the armed police officers wave me across to the diagonal corner — “look for the glint of red carpet” — past the sentry guards and the formal front gates, that once I leave I am unlikely ever to be invited back.

Where does the story of this interview begin? Perhaps with our formidable planning team, led by Sam McAlister, who a full year earlier had approached the Palace to ask Prince Andrew to sit down and talk. Perhaps it begins in May, when the Palace returned the interest, suggesting that he might want to discuss a whole range of things — trade after Brexit, his projects, and Britain’s place in the world. His friendship with the convicted paedophile Jeffrey Epstein was the one area they did not want discussed.

There is no easy way to ask a senior member of the royal family if they had sex with a minor.

This rings alarm bells with our deputy editor, Stewart Maclean. His news antennae — and discomfort with being told what can or cannot be addressed — will become instrumental to this whole process.

And so we decline — just out of principle. Red lines are never a good starting point for any interview.

But two months later — in a bizarre twist we never saw coming — Epstein is arrested on further charges of trafficking and exploitation of dozens of underage girls. And is found dead in his New York prison cell in August. As we learn the scale and breadth of his exploitation. As his victims come forward to speak out — sometimes for the first time.

Windsor Castle, We Have a Problem

Prince Andrew had known Epstein and his girlfriend, Ghislaine Maxwell, for a decade. He had stayed with them, travelled with them, partied with them. What’s more, he had been named in the legal deposition of one woman — Virginia Roberts — who claimed that she had been trafficked to him for sex on three occasions. What did the Duke of York actually know of Epstein’s behaviour? And what had he himself done? Those questions were becoming harder to leave unanswered.

The Palace knew they had a problem. They had sent out statements vigorously denying the claims. But those perhaps lacked the conviction of a human voice behind them. And so we go to meet his team. They feel that a Newsnight interview is the only way to clear the air. To put across his side of the story. We feel we can afford no editorial interference. This cannot be a walk-round-the-garden chat — with a quick, euphemistic allusion to the scandal at the end. All the usual royal protocol will be out the window. This has to confront the issue head-on. Take the elephant in the room. Sit it down. And hear it speak.

He had stayed with them, travelled with them, partied with them.

Our talks are candid. All they demand from us is an open mind.

We discuss the now infamous photo that appears to show the prince’s arm around the waist of a 17-year-old Roberts. Some of his friends had called it a fake. Were they suggesting the same thing, I ask. They shrug. “We just ask you to consider everything.”

Our investigations unit had been sifting through the timelines, the court depositions, the photos, the money that’s changed hands. We had tried to determine what had come from media interviews and what had come from legal documentation. We endeavoured to match up dates and places. Quotes and witnesses. Then, on Monday of last week, we return to Buckingham Palace. We propose a 40-minute extended interview — with a set-up piece to explain the background of all that had been said. This time, it will — fittingly — be Stewart’s candour that will ultimately get the whole thing over the line.

Capturing the Queen

We have finished laying out our pitch. An awkward moment of silence falls. And the duke tells us he must “seek approval from higher up”. It dawns on us then that he means the Queen herself. At 8am the next day we have a message telling us to call his office. The Queen, it seems, is on board.

From that moment the week becomes a blur. We have set up the interview for Thursday, and for two days I must carry around the weight of what we’re about to do without breathing a word. We draw up a list of far too many questions — every allegation, every twist in the narrative, everything we genuinely do not understand. We role-play the interview in an office the size of a kennel. The Newsnight editor, Esme Wren, takes the part of Prince Andrew and she bats away my putative questions by telling me — in assumed character — they’re “improper” or “tasteless” — unbecoming of the BBC (she is, as it turns out, fiercer, more obfuscating and more threatening with me than the prince will be).

We role-play the interview in an office the size of a kennel.

It is impossible ever to feel ready for an interview like this one. It will be one of a kind. But at 1pm on Thursday I am bundled into the cab to the palace, with Jake Morris, the investigations producer, at my side. He has researched each question, cross-checked dates and quotes. “What if I forget to ask about the photo?” I panic. “What if I don’t dare talk about sex in a bath?”

“I’ll shout out anything you forget,” he says. It is too odd a thought even to contemplate. But at that moment I just believe he will.

This time, once we cross the courtyard of Buckingham Palace, we are taken into the Queen’s own entrance. We will film in the south drawing room — in truth, a modest ballroom — and we will reach it through a seemingly endless journey the length of the extraordinary Marble Hall, where investiture ceremonies are performed. The walk is dazzling, stately and, frankly, intimidating.

Panic Attack

I am trying to understand the significance of the Queen giving us her own formal quarters in which to film, but it feels like a code I do not properly understand. Is she endorsing her son? The need for this interview? Or am I reading way too much into every step, merely because there are so many of them? The door to the stateroom opens before me and all I can focus on is the carpet, a swirling, blinding riot of reds and yellows.

It is making me dizzy, but I can’t take my eyes off it. Which is why, as I trip into the room, Bag Lady Supremo, I do not realise the duke is there before me. I have no free hand to shake. And if I curtsy now I may not make it back up again.

I quickly sidle off to the loo, see I have chocolate on my teeth, and start to scrub with what I realise too late is a palace hand towel.

This is the most disastrous start to any interview I can imagine. And then I suddenly recognise it for what it is: pure stomach-gripping nerves. And the recognition of something so obvious relaxes me.

The Duke of Hazard

Back in the room, the duke and I begin the preamble — small talk. He seems at ease, fascinated by the mechanics of the whole process, laughing at the number of cameras Keith and Jonathan have set up. The sound engineer, Paul Cutler, comes to mike me up. The duke notices a trail of a wire from my jacket and is looking pained. His engineering brain has kicked in and it seems to him really obvious the wire should be on the other side, tucked around the opposite edge of the chair so it won’t stick out. He starts directing the mike placement until the cameraman and the sound engineer are following his orders. He finally sits back, satisfied that he has solved a technical conundrum for the team. He does not seem particularly nervous. He doesn’t seem like a man who’s about to decide his own fate in an on-camera interview.

We start to roll. My opening question must be broad and encouraging. But it must also nod to how extraordinary this moment is. We are in the heart of Buckingham Palace and we are interviewing a senior member of the royal family about his paedophile friend Jeffrey Epstein and his own sexual conduct. The grandeur and splendour of the setting are throughly out of kilter with the seediness of the subject.

He doesn’t seem like a man who’s about to decide his own fate in an on-camera interview.

“Your Royal Highness,” I begin, “we’ve come to Buckingham Palace in highly unusual circumstances. Normally we would be discussing your work and duty. Today you’ve chosen to speak up for the first time. Why have you decided to talk now?”

I’m expecting him to embark on a long ramble about his work and his royal duty. But he doesn’t. He does something that stops me in my tracks. He just answers the question directly. “Because there is no good time to talk about Mr Epstein and all things associated, and we’ve been talking to Newsnight for about six months …”

Memory Lapse

The elephant, it seems, has joined us. Right from the word go. And it is a relief to me to hear the name said out loud, an acknowledgment we are both here to discuss the thing we knew we must. And thus begins the most extraordinary encounter of my professional life. A man who has not talked publicly on this subject for a decade has now been permitted to do so and won’t stop.

He tells of their friendship, and what he got from it. Tells of Ghislaine Maxwell, and how she had been the initial link. And he is vehement in the denials of his own wrongdoing. He cannot ever remember meeting Roberts, he tells me. I am trying to understand if he knows he didn’t or if he just can’t remember. It seems a vital difference. And I need to hear which he believes.

He pauses, thinks briefly, and tells me: “No, I have … I don’t know if I’ve met her, but no, I have no recollection of meeting her.”

Other things bring more clarity. He has come prepared to admit that he made a grave error of judgment — staying with Epstein after his conviction. He let the side down. “The side” being Buckingham Palace and all it stands for. But when I ask if he regrets the Epstein friendship I get a breathtakingly candid “no”.

He talks about the “opportunities that I was given to learn by him” and he tells me he’s guided by honourable behaviour, by which I think he means that you can’t break up with a mate (who is a convicted paedophile) without doing it in person. He must have known what Epstein was like, I press. Roberts’s legal team has said that you “could not be around Epstein and not know”. The duke reminds me that he was a patron of the NSPCC. He would recognise “what the things were to look for”. He swears he never saw them.

But when I ask if he regrets the Epstein friendship I get a breathtakingly candid “no”.

By now his words will have been pounced on and poured over. Bitten off, spat out. Chewed and, maybe, swallowed. People will make their own minds up about what they heard and saw. And some minds will have been made up long before they even saw him speak to me.

In person he is courteous, affable and eager to please. There is no question that he shies away from, no issue with which he refuses to engage. Indeed, I reflect afterwards that there have been more riders and red lines drawn in the interviews I’ve done with C-list celebrities and backbench politicians than with the Queen’s reportedly favourite son.

From an interviewer’s perspective he has been everything you could ask. Approachable and expansive, polite and generous with his time. He has given me fresh detail, new thoughts and told me things I had certainly never heard before. It is what we want from every encounter. It is what we long to hear.

The Crown Avoids The Crown

Our news world is so often full of bland figures trying willfully to be more bland. Say nothing. Avoid scrutiny. Dodge and deviate from every question asked. And whatever comes of this, I must admit to respecting an interviewee who is prepared to approach head-on every single thing that he is asked.

As we part, he walks me back down the Marble Hall until we stop at a statue of Prince Albert. “The first royal entrepreneur,” he tells me proudly. “Next time you come, we will talk about [his entrepreneurs’ initiative] Pitch at Palace.” It nods to the fact he feels he can now get on with the work he loves. But I probably shouldn’t wait by the phone.

Back in the south drawing room I collect my bags. The floor is being transformed by palace workmen. It looks for a minute as if railway tracks are going down. The kind young woman who has shown us in sees my confusion. “It’s for the Buckingham Palace cinema,” she tells me. “All the people who work here come along. It’s Judy tonight if you want to stay.” But my day has already hit peak surreal and I think I need to disappear.

“Perhaps you want to get everyone along for Sunday,” I say. “It’s the new series of The Crown.” She looks momentarily apologetic. “We had Downton Abbey last week. But we don’t do The Crown here.” With that, finally, it feels time for me to leave.