As personal protection officer to the late Diana, Princess of Wales, Ken Wharfe was in charge of round-the-clock security at home and abroad, from 1987 until 1993. He retired from the Metropolitan Police in 2002, after 35 years' service, nearly half of it in royalty protection. He was then appointed a Member of the Royal Victorian Order, an honour in the Sovereign's personal gift. Here, in an excerpt from his new book, he describes life with the dazzling but unpredictable Diana . . .
Dressed down in jeans, T-shirt and her favourite blue blazer, Princess Diana imagined she looked inconspicuous as she joined a line of holidaymakers at a Gatwick check-in desk.
It was probably the first time she'd queued since her marriage. But she was determined to be 'normal' for once - and that meant going on a budget flight in what she laughingly called 'goat class'.
Unfortunately, she was recognised by some rowdy girls from Essex on their way to a hen party weekend in Ibiza. At first, they could barely believe who was standing in front of them.
"It's bloody Diana! Look, it's the Princess!' said one in a stage whisper.
'Bloody hell, so it is!" said another.
"Shouldn't she be in first class?" chipped in another.
Within seconds, we were surrounded and more heads were turning in Diana's direction.
"Can we have a photo together, your 'ighness? It's her hen weekend," another of the party said, pointing towards one of her friends.
How would we get out of this? Diana was looking disconcerted, but as her personal protection officer, I knew she wasn't in any danger.
So, mischievously, I let the situation unfold a little longer . . .
It had been the Princess's own hare-brained idea to take a budget flight to Aix-en-Provence, just like any other member of the public.
"I want to go away on holiday but I don't want any special treatment, no fuss. I want to be just like everyone else. I want to be like normal people," she'd told me.
The curveball came from nowhere, and I knew it would be particularly tricky to manage.
"Really? Are you sure, Ma'am?' I asked. 'It will present some . . . well, shall I say, logistical challenges. Of course I can make the arrangements as you wish, Ma'am, but to be frank . . . well, you're not like everyone else."
This was not what she wanted to hear. She flushed and puffed out her cheeks.
"Ken,' said Diana, breathing deeply - always a sign that I might have overstepped an invisible mark when she was in one of her moods - 'can you please just make the arrangements as I said. That is what I want."
At this point, in the spring of 1989, I'd already been guarding her for two years. And I'd learned to my cost that Diana, Princess of Wales could be a difficult woman to please.
When she was on top form, there was no one better; when she wasn't, it was best to give her a wide berth - not that easy when you were her protection officer with a duty to keep her safe. This time, her heels were well and truly dug in.
I knew full well that her madcap scheme would go one of two ways: either it would result in a total calamity, for which I'd doubtless be blamed, or it would be scrapped altogether and normal service would be resumed.
Because, of course Diana was not like any other passenger. She did have a passport, but that was as close to normal as she got. Hers - number 125580 - had 'Her Royal Highness The Princess of Wales' emblazoned across the front.
And instead of stating her nationality, it simply read "Princess of the Royal House', which always made her giggle. Plus, she'd signed it with the single name Diana, and boldly underlined it.
Travelling can be dreary: standing in line at security, luggage allowances, plane delays, jet lag and strange hotels. But it wasn't like that for the Princess of Wales, who was used to private jets, royal helicopters and billionaires" yachts.
Even when she took a commercial flight, the Princess was driven straight to the plane by limousine, or we'd be temporarily entertained in one of the VIP lounges.
Her documents would be dealt with separately, and her luggage - emblazoned with the letter D and a crown - handled by the airport Special Services. Anyway, the big day arrived when the Princess would be voluntarily downgraded to 'goat class'. I arrived early at Kensington Palace so we could head off to catch the Gatwick Express from Victoria.
"Why do we have to leave so early?" she complained. 'The flight isn't until 3pm and I have a hair appointment at 11.30am."
"Well, I can't see how you can make that appointment, Ma'am, and queue for luggage, then go through security in time," I replied. "We will miss the flight as we have to take public transport, too."
She looked at me quizzically. "Really, as long as that?"
We compromised: I asked her chauffeur to take us to Gatwick as soon as the hair appointment was over. So by the time we arrived, we were running late and the queues were horrendous.
Soon, we were ringed by around 20 people, all vying to get a better look at the Princess.
After a minute or two, Diana shot me a look. Without her having to say a word, its meaning was clear: "I'm a Princess . . . Get me out of here!"
Fortunately, I had a Plan B. Without telling Diana, I'd contacted airport Special Services the day before and explained the situation. They'd promised to help out, if I needed them.
The Princess and I began walking away. "Where are you going, Di? I wanted just one more photo!" cried one of the hen party girls. Seconds later, normal service had been resumed, and we were being whisked through security.
Diana was offered a glass of water in the sanctuary of the VIP area, which she accepted with a smile. She didn't say a word about what had just happened.Yet Diana was always dreaming or conniving at an escape from the strictures of life as a Royal.
Being at the centre of a gathering of hen party revellers was an anecdote she told many times, accompanied by screeches of laughter. She usually concluded it by saying she would have been happy to join in the girls' fun. In reality, I knew that nothing could be further from the truth.
Yet Diana was always dreaming or conniving at an escape from the strictures of life as a Royal.
Her favourite pastime, especially around December, was flicking through upmarket holiday brochures to find an escape from the formality of a royal Christmas at Sandringham. She always felt suffocated there, she told me.
In fact, it wasn't her husband's family she really wanted to escape from, but Prince Charles. At this point, both had taken lovers and they were often barely on speaking terms.
Surfing through holiday brochures was a form of escapism that made Diana feel normal, as though she, too, could just jet away on a package holiday, like other people. And without Charles.
Even a three-day private visit to the ancient Italian city of Verona could make all the difference to her mood. It was August 1990 and I had seldom seen her so happy.
Diana and her mother, Frances Shand Kydd, were staying with Frances's old friend, the Contessa Maria Cristina Loredan Guerrieri-Rizzardi. One evening, we all slipped out to an ancient arena to hear Luciano Pavarotti perform Verdi's Requiem.
The great tenor held his audience spellbound. Then, about halfway through the Requiem, the heavens opened, and even our umbrellas failed to stop the torrential rain from soaking us to the skin.
Nothing, however, could dampen Diana's spirits. She was elated, by the music, the atmosphere and the dramatic setting, and wanted the evening to go on for ever.
Pavarotti had spotted the Princess during the performance, and as he left the rain-drenched arena, he invited our entire party back to his dressing-room. There, in his broken English, he flirted outrageously with the already smitten Diana.
When she left, she was on fire. As we stood beneath a tarpaulin, waiting for the cars, she suddenly declared that she wanted to go to Venice. "Ken, we've got away with it. Nobody knows we're here, not even the local Press. Let's live a little," she said, beaming.
It was close to 10pm, but I knew from her expression and her manner that nothing was going to stop her seeing Venice that night - even if she had to walk there.
In minutes, Diana, her mother and I were heading for Venice, along with the flabbergasted British Consul, Martin Rickerd, who seemed bemused by our lapse into insanity.
We arrived at the police headquarters of Venice just after midnight. Jumping out of the car, Diana starting kicking the puddles, as if she were Gene Kelly in
Singin' In The Rain
The Venice police arranged for two motorboats to take us to see the city by moonlight.
For the next hour, we saw Venice as few have been privileged to do. We sailed along the Grand Canal, armed with a bottle of chilled Pinot Grigio, from which Diana would take the occasional swig.
She then announced she wanted to walk through St Mark's Square. It was a surreal experience. Apart from a couple of vagrants dossing down, we were the only people there.
As she took another swig from the bottle, Diana - eyes alight with pleasure - turned to me. "If only I could have this freedom once a month, it would make the job worth it all the more," she said.
The Princess knew she had a life of great privilege, and she didn't blame anyone for the restrictions placed on her. But she often longed to do the things so-called ordinary people took for granted.
A couple of years after her Venice expedition, in May 1992, Diana asked if I could allow her to take a long walk along a beach, without me at her side. My Scotland Yard superiors would have gone potty if they'd known, but I promised I'd make it happen.
From my childhood, I recalled the sandy beaches of Studland Bay on the Isle of Purbeck in Dorset, and thought they'd be ideal for her cherished solo stroll.
Less than a week later, we drove to Sandbanks ferry at Poole in a saloon car. Diana was hugely excited, and fortunately none of the passengers recognised her.
Half a mile from the ferry landing point, we crossed a wooden bridge to the deserted beach of Shell Bay. There was no one around except a few oystercatchers and other birds stabbing at the wet sand.
I gave Diana a two-way radio and a map I'd sketched of the shoreline, and said I'd meet her at the far end of the bay in a pub car park. Then she left - a tall, slim figure in denim jeans, a suede jacket and a scarf wrapped around her face to protect her from the chilly wind.
I watched as she disappeared into the distance. It was a strange sensation, watching the wife of the future King walk away by herself.
As the Princess disappeared from view, I radioed her. Her voice was bright and lively and I knew she was revelling in her freedom.
Knowing the walk would take around 40 minutes, I sat on a wall in the spring sunshine. Suddenly my radio crackled into life.
"It's me, can you hear me?" she said. "It's amazing! I can't believe it,' she said, sounding exhilarated. 'You could have told me about the nudist colony!
She burst out laughing and I did, too. It simply hadn't occurred to me that nudists would venture out on such a crisp spring day. As she finished her walk, I saw her throwing sticks for two dogs that had joined her at the water's edge.
There were no crowds, no security apart from me, no over-attentive officials, no servants. For once, Diana felt truly 'normal'.
Normality was certainly lacking in her private life. As her personal protection officer, I was often in the unenviable position of witnessing her rows with Prince Charles.
One memorable occasion made a particular impression, not least because it had its lighter moments - but also because it summed up the distance between the couple, as well as Diana's absolute lack of appreciation of her husband and his sense of humour.
It was the evening of the state banquet for the King of Norway, and I was handling security for both the Prince and Princess.
Diana was in a particularly impatient mood. She was tapping her feet in frustration - at having to attend this formal function, at her husband, at having to dress to the nines, at delays and any other irritations that came to mind.
In complete contrast, the Prince was extremely relaxed. He knew the form on state occasions like this, when all senior - and many of the so-called 'minor' - members of the Royal Family were on parade. Everything had to be done in almost military fashion.
Royalty would arrive according to ascending order of rank, with the most senior, the Queen herself, arriving last, at exactly the time listed in the programme.
It might sound absurd, but this is how the business of monarchy works - and state banquets, when the principals turn out in all their finery, tiaras, dress uniforms, evening dress, decorations and all, are when the business of royalty becomes very serious indeed.
But Diana did not quite see it like that. As far as she was concerned, a state banquet was an irritation, something to go to, to be seen at, and get home from as early and unscathed as possible.
In the mood she was in tonight, this was doubly, or trebly, the case.
The Princess and I, in evening dress, were in the hall of the apartments at Kensington Palace, waiting to set off in the car according to the order of precedence.
She sighed and turned to me. "Can we go early? I don't want to hang around here any more," she said. There was a faintly childish whine in her voice.
"Ma'am, it's really not as simple as that, there is an order . . ."
She snapped back: "I know all about their bloody orders, I know all about them! I want to go now. Simon [her chauffeur] is ready and I want to go now."
Fortunately, Charles, also in evening dress, appeared in the hall right on cue, tugging on his cuffs in his slightly nervous manner, like an actor in a West End comedy. He clearly sensed an impending tantrum from his volatile wife.
"Are we ready to go?" he asked me. There was a stony silence from both of them as I pointed out that it was not our slot yet. "Have I got time for another Martini then?" he asked politely.
I couldn't help smiling broadly. It struck me as vaguely absurd that the future King was asking me if he had time for another drink.
I told him that he probably did have time. The frost emanating from his wife became icier.
"Is anything the matter?" he asked, not directing his question to anyone in particular.
"Well, Charles, there is, actually," said Diana, spoiling for a fight. "I want to go now, I don't want to hang around here." There was a dangerous edge to her voice.
"You know the system," he replied reasonably. "We have to go at the set time, so that we arrive just before Her Majesty."
Diana, drawing herself up in her high heels (or 'tart's trotters' as she called them), turned on him: "But Charles, why can't you go on your own? I can get there earlier. Nobody will worry about me."
Of course she knew that if she turned up without her husband, the waiting media would plaster it all over the front pages, speculating, quite rightly, that the Prince and Princess had had another row.
Charles, who clearly did not want a fight, retreated, asking the butler, Harold Brown, for another Martini.
When he left, I told the Princess I thought the whole row was silly. It was not what she wanted to hear, and she sounded off again.
I was actually trying hard not to laugh, partly at the ridiculousness of the situation and partly at her husband's antics.
A few minutes later, the Prince re-emerged, as his wife paced up and down like a caged animal.
"Charles, I have really had enough of this. I'm off," she fumed.
"No, Diana, we really have to wait," he rightly insisted.
Charles ordered another Martini and departed again, and at this point I let out a little chortle.
"What is the reason for the delay?" the Prince asked, reappearing.
"Actually, Sir, the Princess Royal is stuck in traffic at Hammersmith," I told him, to which he replied with a wry smile, "Oh, not again!" He carried on with his drink.
"Do you find my husband funny?" Diana snapped, by now extremely irritated. "Well, do you?"
I paused for a second, then said: "Actually, I do, Ma'am. I think he has a great sense of humour." Foolishly, I then added: "It's not too far removed from my own."
"So, what kind of humour is that?" she retorted curtly.
Too late I realised I had said the wrong thing. Diana did not find her husband funny, nor should her protection officer. For the rest of that night she said not a word to me, other than perfunctory answers to my necessary questions.
As for Charles, no one at the banquet could have guessed from his calm demeanour that he'd survived a domestic sniping attack. Or, indeed, that he was already a good few Martinis down.
That summer, the Princess reluctantly agreed to join her husband and children on a Mediterranean cruise on a super-yacht owned by billionaire John Latsis.
A couple of weeks before we were due to sail, she suddenly refused point-blank to go, and told the Prince she'd also stop their sons from joining him. This seriously irritated Charles, who was looking forward to a holiday with the boys. In fact, Diana had every intention of going on the cruise - she just took considerable pleasure in unsettling her husband.
From the moment they boarded the yacht, they saw very little of each other. Diana, however, suspected he was spending hours on the satellite phone, chatting to Camilla, and this irritated her.
Soon the atmosphere became extremely tense. Diana wanted nothing to do with Charles and even her sons became concerned about her strange behaviour.
This culminated with a bad scare when a colleague told me she hadn't been seen for two hours. Had she jumped overboard?
We launched a thorough search, but there was no sign. Panic set in. Then I recalled she had spent some time by the lifeboats. In one of them, I found her crouched beneath the canvas cover in floods of tears. She'd been there for two hours.
I spent the next couple of hours in the lifeboat locked in conversation with Diana under the cover.
"He's on the phone to the Rottweiler, and everybody knows it. They are all in it with him. They think I'm mad and feel sorry for me, but they have no idea what I'm going through," she sobbed.
She had a point. Although Diana had been unfaithful, too, she at least had the decency not to flaunt her affairs under her husband's nose.
Having worked herself up into a fury, Diana demanded I arrange for her to be flown home immediately. She wasn't staying on this "floating hell" for one second longer than she had to.
Her plan was to fly by helicopter to Cyprus and board a scheduled flight. But I pointed out that all the flights would be booked solid.
In the end, she agreed to remain. Despite her occasional immaturity, she knew that to make a show of defiance in front of her beloved sons would be unforgivable.
"Come on," she said, "we'd better get back to the rest of them. Otherwise that bloody husband of mine will be cracking open the champagne, hoping I did actually jump overboard and he can make that hideous woman his princess."
Four months later, soon after the official announcement of her separation in December 1992, we flew to the tiny Caribbean atoll of Nevis with William, Harry and Diana's friend Catherine Soames. It was a perfect setting, with turquoise waters, lush rainforests and sandy beaches.
With a few well-thumbed novels of the Jackie Collins-type, Diana could relax in the sun in her bright orange bikini, working on her tan.
She knew it wouldn't be long before the media pack arrived, and she was determined to look her best. For all her fame, Diana recognised her success was dependent on the court of public opinion. If she did not appear in the British newspapers, her star might wane.
Being popular with the masses required hard work and dedication, and she shirked neither.
She often told me she felt a duty to the countless schoolchildren, elderly women, star-struck girls and infatuated men whom she counted among her army of fans.
"They don't want to see me looking dowdy, they want to see me out there doing my thing," she would say.
After a couple of days' sunbathing, she looked magnificent on the morning of the first photocall.
One memorable shot caught her as she emerged from the Caribbean surf, her bronzed skin contrasting with her orange bikini, looking absolutely sensational. Not only would this ensure wide media coverage, but it was a perfect opportunity to send her estranged husband a "glad-you're-not-here" postcard, in the form of stunning bikini shots dominating the front pages back home.
After a week in the sun, Diana, relaxed and refreshed, returned to Britain. "That was the best holiday I've ever had," she said.
It was then that something wholly unexpected happened which strengthened her position still further - 'Camillagate'.
At the end of January, newspapers published extracts from an illicitly recorded telephone conversation between her husband and Camilla Parker Bowles, said to have taken place on December 18, 1989.
It was intimate and distasteful, and the backlash was savage. Loyal Establishment figures were appalled, and some questioned the Prince's suitability to rule.
The Princess, however, enjoyed the moment. "Game, set and match," she said.
• Guarding Diana, by Ken Wharfe with Robert Jobson, is published by John Blake