She (Christine Keeler) was strongly attracted to a daily visitor at Wimpole Mews and Stephen's closest friend at that time, Eugene lvanov, second naval attache at the Russian Embassy. And hardly surprisingly, for Eugene was one of the most charming people I have ever met. Very, very handsome in a James Bond sort of way, very easy to talk to, warm, humorous, generous too - his frequent gifts of vodka and caviar always presented with a little joke about "the luxuries you capitalists appreciate."

With Eugene, Stephen's usually flippant personality took on a more serious note, and they would discuss important political concepts in great depth. The effect was contagious, I would join in these intense discussions with enthusiasm. I really became interested in Russia and very curious about communism when I met Eugene.

Then there was a double wrestling match. Each man took a girl on his shoulders and tried to tip opposing couples into the water. The winner was the girl who was not unseated. Needless to say, Christine and Profumo were a team. This time there were photographs. Some show Profumo, Christine, Ward and other guests. Some were captioned by Profumo himself: "The new Cliveden set" but they were later stolen from Ward's flat. One of the surviving pictures shows Ward, slim and smiling, handsome behind his sun-glasses, with Christine in a one-piece black swimsuit leaning on his shoulder. Resting her head on his thigh is a brunette, Sally Norie, and sitting by his feet is a blonde, both women later to figure in Ward's trial as prosecution witnesses.

Late in the afternoon Ward took Ivanov aside and asked him to drive Christine back to London. He said he had an hour or so's work to do on Bill Astor's back but he encouraged Ivanov to wait for him at Ward's flat so that later that evening they could play bridge. Ivanov agreed, but Ward never kept the appointment. What happened at the flat is unclear. Christine said later that Ivanov took a bottle of vodka from the boot of his car; they drank it and when it became obvious that Ward was not coming to play bridge, they went to bed together. But, as we will see, Christine was encouraged by newspapers to say that she had slept with Ivanov whether she had or not. Ivanov's version was that he got very drunk on vodka while waiting for Ward and when it became late he decided to leave. He said he was so drunk he could hardly find his way home.

Christine's story must be treated with great scepticism. As the barrister John Zieger points out, Christine was quite frank about her sex life and if she had slept with Ivanov she would have said so at the time. On the contrary, at the time she actually said she had not slept with him. "Two or three weekends later she was gossiping about it," Zieger remembers. "She said Ivanov had been drunk and she was amused by his wavering along the line of being a Russian married man and amorous at the same time. And she said he went off. It was only 18 months later when people were pursuing her and she had a story to sell, and it was only a good story if Ivanov and Profumo were sharing a mistress, that Christine decided she had slept with Ivanov. I don't believe she ever did."

What is more important was Ward's motive in deliberately throwing Christine and Ivanov together. If he really had to treat Astor, what was to prevent Ivanov and Keeler from waiting for him at the cottage? Then they could all have driven back to London together. If he was baiting the "honey-trap" for Ivanov then it was a strange way of going about it, since Ivanov was smart enough to see what was happening, having been trained to recognise such risky situations and having learnt to avoid being compromised. (Would a Soviet GRU officer really have intercourse with a girl steered his way in the flat of a man he knows is in contact with the British security services? Any intelligence officer, Soviet or Western, would automatically assume in such circumstances that he would be photographed and blackmailed.)

What is not speculation is that first thing on Monday morning Ward telephoned his case officer, Woods, and went to see him. He gave him several significant pieces of information: that he had pushed Keeler in Ivanov's direction; that Ivanov and Profumo had met at Cliveden; that Profumo had shown interest in Christine (Profumo had asked Ward for her telephone number); and that Ivanov had asked him when the United States was going to arm Germany with atomic weapons. This flood of information was almost too much for Woods to handle. The routine entrapment operation was becoming complicated.

Woods was not concerned about Ivanov's interest in Germany and atomic weapons - that was to be expected of a serving GRU officer. But Profumo's interest in Keeler could interfere with the honey-trap. The aim was to catch a Russian in an indiscretion, not a British Cabinet Minister. Woods decided he was out of his depth. This was a matter for his Director-General, Sir Roger Hollis.

We drank and talked more about his country. He bragged about the size of Russia, how much had been achieved by the Party, how loyal its people were. We drank glasses of vodka and he got annoyed because I kept putting tonic in mine. Then he started kissing me. He wasn't very enthusiastic at first but it was clear what he wanted to do and he got carried away. I could feel him get more excited. He thrust me to the floor. He took his time. He wanted good, old-fashioned sex without any fuss or trimmings. He was a Soviet warrior. He did what Stephen had ordered him to do. And he was pretty good at it.

I had just had sex with a Soviet spy, a man from Moscow. If anything went wrong from now on I was the wanton woman who had betrayed her country by bedding a spy and selling secrets. I was not that willing a partner and he didn't like it much either but he'd carried out his orders, even if it made him feel a little ashamed of himself.

On 22 January 1963 came the logical outcome of Christine Keeler's contacts with the Sunday Pictorial, the newspaper that had infiltrated Keeler's circle through her friend Nina Gadd. For a down payment of £200 - and the promise of £800 to come - Keeler told, the Pictorial everything. With the deft help of professional, an accurate draft story was assembled. The truth was told better in this first draft than it ever would be when Fleet Street finally broke into print. Speaking of her relations with Profumo and Ivanov, Keeler said: "If that Russian ... had placed a tape-recorder or cine camera or both in some hidden place in my bedroom it would have been very embarrassing for the Minister, to say the least. In fact it would have left him open to the worst possible kind of blackmail - the blackmail of a spy... This Minister had

such knowledge of the military affairs of the Western world that he would be one of the most valuable men in the world for the Russians to have had in their power..."

The article referred to the request that Keeler ask Profumo about nuclear-armed weapons for Germany. Finally, as proof that there really had been an affair, Keeler gave the journalists Profumo's letter of 9 August 1961, addressing her as "Darling". A copy was placed in the safe at the office of the Pictorial. The story was dynamite, but, as is the way with Sunday newspapers, the editors did not rush into print. What with cross-checking, and the need to have Keeler authenticate the final version, nearly three weeks slipped by - time for much skulduggery.

Four days after telling all to the Pictorial, on Saturday 26 January, Keeler had a tiff with Stephen Ward. It happened when Ward, not knowing that Keeler was listening in, had a telephone conversation with Keeler's current flatmate. The Edgecombe shooting incident was proving a nuisance, and he burst out: "I'm absolutely furious with her ... she's ruining my business. I never know what she'll do next, the silly girl..."

Keeler was angry. What she did next was to tell the Profumo story all over again, this time with Ward as the villain of the piece, the man who had made all the introductions. She told the story to the next person who came to the door, who by unhappy chance was an officer in the Metropolitan Police calling to say that Keeler and Rice-Davies would have to appear at John Edgecombe's trial. The detective listened to Keeler, then went back to the office and filed a report. It included all the main elements of the story, along with the allegation that "Dr Ward was a procurer for gentlemen in high places, and was sexually perverted," and the fact that the Pictorial already had the story. The detective's report went to his Inspector, and - given the content - he passed it on to Special Branch, the police unit which liaises with M15.

That same Saturday, Stephen Ward learned from a reporter of the impending story in the Sunday Pictorial. He was the first of the principal male characters to learn of impending disaster. Ward at once demonstrated a loyalty to his friends that none of them would ever show towards him. "I was anxious," he said in his memoir, "to save Profumo and Astor from the consequences..."

Next morning, Monday the 28th, Ward called Lord Astor. The two men met, Astor also took legal advice, then personally took the bad news to the Minister for War. The time was 5.30 p.m.

Profumo's immediate response was remarkable - he urgently contacted the Director-General of M15, Sir Roger Hollis. It was an unusual procedure for a minister of Profumo's rank to call in the head of M15. Yet Hollis was sitting in Profumo's office in just over an hour. Both men, of course, remembered the occasion in 1961 when MI5, through the Cabinet Secretary, asked Profumo to take part in the Honeytrap operation to make Ivanov defect. Now, so far as Hollis could tell, Profumo wanted help in getting a "D Notice" - a Government gag - slapped on the Sunday Pictorial. Hollis failed to oblige.

It was later reported that Eugene was recalled to Russia in January 1963 - I believe he left London in December. Stephen was as mystified as I was. "He's probably been sent back to Moscow," he said to explain the absence of his friend, but he was hurt at not having had the chance to say goodbye.

If Ivanov was a Russian agent, and his masters decided to whisk him away before the Profumo scandal erupted, why not complete the charade and allow him, in the character he portrayed as just a very charming embassy official, to ring his friends and say farewell. Why such a mysterious departure? It was an anomaly that bothered me for many years.

Three years ago I had my answer. I was filming in Israel. I had just announced my engagement to a multi millionaire and been interviewed on the subject. When I was told that two reporters wanted to interview me for Time magazine, it seemed reasonable. However, their choice of hotel, and especially their suite, seemed rather extravagant for journalists' expense accounts.

The spokesman of the two immediately came clean. They were not reporters but private investigators from New York, investigating on behalf of a wealthy client one of those messy domestic wrangles involving paternity claims and so forth. The woman in question, to provide an alibi for a period in her life, had named me as a friend in London at a particular time. I did not recognise her name, or her photographs.

"Sorry, I can't help," I said. "Incidentally, you don't even look like newspaper reporters. You look more like the CIA".

They smiled at this. "Right first time," said the chatty one. "I was with the CIA for twenty-five years. I spent a lot of time in London - I was involved in that George Raft affair at the Colony Club."

"You'll probably remember the Profumo scandal," I said. "What did you make of Eugene Ivanov? What ever happened to him?"

He gave me an odd look. "Don't you know? We took him."

"What do you mean, you took him?"

"We. The CIA. We couldn't let him go. We didn't know what he had, and what he didn't have, and we didn't want to take any chances. Let's say he was an involuntary defector."