AN AFFAIR OF STATE The Profumo Case and the Framing of Stephen Ward By Phillip Knightley and Caroline Kennedy Atheneum. 268 pp. $18.95

AT ABOUT the time Gary Hart's presidential campaign was self-destructing last May, I was passing through London on a European tour. The Hart story was big -- and in many quarters, baffling -- news. "For God's sake, America, grow up," cried a commentator in the London Evening Standard. That was the theme on the continent as well: "Washington loves a sex scandal," a Belgian pundit wrote -- the implication being that Europeans don't. A French sage scoffed at the very idea that the American voter, before inquiring into a candidate's program, should want "to know first if he's cheating on his wife." The consensus was clear: We Americans are fundamentally different, in some weird, Puritan (or prurient) way, from our British cousins in particular, but from most other Europeans as well.

Or so I was persuaded until I came across excerpts in the London Sunday Times of a forthcoming book about a British sex scandal in the 1960s that wrecked the brilliant career of a young Tory politician already penciled in as prime ministerial material; came close to bringing down the government of Harold Macmillan; reached into the royal family; scorched the high and mighty of British society and the elite of the political establishment; rattled the ruling Kennedy entourage in Washington; and culminated in a callous cover-up that, the authors claim, finally drove an idiosyncratic but innocent scapegoat to suicide.

You could wrap the Gary Hart story up with Watergate and throw in a few lesser cases of American official misdeeds and it would be a close question whether the aggregate would outmatch the seamy, steamy story told in An Affair of State: The Profumo Case and the Framing of Stephen Ward in terms of malfeasance, broken faith, wanton promiscuity and other deep deficiencies in the character and performance of trusted and respected public officials.

But you can judge for yourself; An American edition has become available in bookstalls here. I recommend it; it would be a corking good yarn -- all about sex orgies, espionage, dirty tricks, dishonor and hedonism in high places, with a rich cast of characters -- even if it were pure docudrama. But this story is true: The central facts are a matter of public record. What the authors, investigative reporter Phillip Knightley and free-lance writer Caroline Kennedy have added -- which is a lot -- has the ring of authenticity derived from hard-digging for new angles having to do with aspects of the case that, as far as I know, have never been dealt with in such riviting detail.

The downfall of John Profumo would have been scandal enough: Her Majesty's Secretary of State for War, married to a beauteous movie actress, Valerie Hobson, and caught up in an affair with Christine Keeler, a call girl who was on intimate terms, as well, with the assistant naval attache' at the Soviet Embassy who doubled as a KGB agent. The security implications were sufficiently grave to engage the attention of the FBI; there was the added suspicion that President Kennedy might have, at one time or another, crossed Keeler's path. First, Profumo flat out lied to the House of Commons about the whole story and then, when the truth came out, confessed and resigned in disgrace. That's what most people remember about "the Profumo Affair," if they remember anything about it at all -- the unforgivable lie. But the most interesting character in the recounting by Knightley and Kennedy is not Profumo but Stephen Ward, who introduced Profumo to Keeler and also introduced Keeler to the Soviet spy.

No snapshot of Ward suffices: He was a practicing osteopath, trained in the United States, whose patients included Winston Churchill, Joseph Kennedy, Frank Sinatra and King Peter of Yugoslavia and a talented portrait artist whose subjects included Prince Philip, Prime Minister Macmillan, Archbishop Makarios, Peter Sellers and Sophia Loren. He was as nimble a social climber as you will ever meet, with a thing about prostitution which is never really explained. Ultimately he was to become the fall guy for the Establishment, hauled before the bar on what the authors claim were trumped up charges of brothel-keeping, abortion offenses, and living on the earnings of prostitutes; at all levels, the British law enforcement process, we are told, was in on a conspiracy to mitigate Profumo's disgrace by making Ward the source of all the evils in "a huge, sticky web" of "sexual decadence and debauchery" in London's high society. Convinced the fix was in, Ward took an overdose of drugs in mid-trial.

IT IS Ward's story that clearly most fascinates the authors, and understandably so, for it is their uncovering of the cover-up that breaks the most significant new ground for British readers. The American reader, with a particular British stereotype in mind (a bit prim, somewhat on the stuffy side, even straitlaced) will discover that life in the British fast lane is not all that different than what we keep finding out about the hijinks of our supposedly brightest and best; that we are not so uniquely excessive in our taste for the sensational as our European critics claim; that we are also not alone in our commercial exploitation of political scandal (Keeler actually incorporated herself as Christine Keeler Company Limited). You will find that it takes longer for scandals to break in Britain owing to tougher libel laws and stringent rules about contempt of court governing pre-trial publicity (and what Knightley and Kennedy condemn as a "chicken-hearted approach" to these constraints on the part of the British press) but that the British appetite for this sort of thing is no less keen on that account.

In the end, one is pretty well persuaded that Ward was cruelly used. But in their zeal to make that case, the authors give short shrift to what happened to Profumo and to a point of more than passing interest in any comparative study of how these matters are handled here and abroad. It is said that we give a bad name to public service by being too beastly to our public figures. But if that is so, it is worth considering the disparate fates of Profumo and some of our fallen figures -- Richard Nixon, say, or Gary Hart. The latter continue to lay claim to an audience for their judgments on the great issues of our times -- and find it. Profumo does penance to this day as a charity worker in the slums of London's East End. For this quiet service he was made a commander of the British Empire in the Queen's 1975 Honors List -- royally forgiven, you could say, but also forever forgotten as a force in British public life.

Philip Geyelin is a columnist with The Washington Post Writers Group.