As a self-proclaimed British master spy, his real-life exploits may owe more to Walter Mitty than James Bond.

But, "Colonel" John Edward Cottell, MVO, MC, MBE, was a hot attraction on the chicken-salad circuit, enthralling lecture audiences with tales of patriotism and valor drawn from his career as a British agent in the 1940s and 1950s.

For the past four years, the tall, dapper Englishman with a carefully trimmed military mustache across his stiff upper lip appeared before more than 300 Rotary Club luncheons, ladies' socials and literary league soirees in parlors from Richmond to Houston, garnering rave reviews and fees of $2,500 a lecture.

Cottell claims to have been an intimate of former British prime minister Winston Churchill and such illustrated British spies as Greville Wynne (who was imprisoned by the Soviet KGB) and Maurice Oldfield (late director of MI-6 and alleged model for John le Carre''s Smiley).

Moreover, he says his own exploits have inspired more than one noted spy novel, including le Carre''s "The Spy Who Came in From the Cold" (Cottell purports to be the model for Alec Leamas, the main character) and the same author's later masterpiece, "Tinker, Tailor, Soldier, Spy," in which, Cottell says, he is Jim Prideaux, the British agent whose capture in Eastern Europe touches off Smiley's epic mole hunt.

Cottell's stirring story, which ends with a flourish of anti-communist and pro-Reagan rhetoric, has received standing ovations from paying customers across Rotary Club America. But his performances have attracted less than rave reviews from his former "colleagues" in British intelligence. John le Carre' has disowned his supposed inspiration, and Greville Wynne has denounced his self-confessed comrade in arms. The British government says it has no record of Cottell's ever serving as an officer in any of Her Majesty's services.

Cottell and his still-numerous American friends and admirers claim the denials and denunciations are part of a left-wing disinformation plot to discredit a patriotic hero. The fact that the British government says it never heard of him, Cottell and his friends insist, only proves that his story is true: he is now a spy left out in the cold.

Even after newspapers in Kentucky and London several weeks ago raised questions about Cottell's claims of wartime heroics, the speaker himself continued to tread the lecture trail. Robert Keedick, the Connecticut-based booking agent who arranges Cottell's calendar, said last month that he had received no complaints about Cottell and saw no reason to question his credentials.

Recently, however, the previously talkative Keedick has become chronically unavailable to journalists inquiring about Cottell, and his office refuses to say whether it is still taking bookings for the self-professed spy. The once-garrulous Cottell now refuses to discuss his background in any detail without consulting a lawyer.

Cottell's story is literally almost too good to be true. As a teen-ager in 1942, he says, he was recruited as a British intelligence agent and personally ordered by Churchill to parachute into Holland behind German lines. With a lethal cyanide pill hidden in a tooth, Cottell says, he helped the Dutch resistance "blow up trains and kill people silently."

Later, he says, he was captured by the Germans and personally sentenced to death by Gestapo chief Heinrich Himmler. He narrowly escaped death only to be sent to the Buchenwald concentration camp, where he was liberated by Gen. George Patton's 3rd Army. He lived to be decorated after the war by King George VI and his friend Churchill, who also taught him how to paint.

During the Cold War, Cottell claims he was recalled to active duty in Her Majesty's Service. This time MI-6 dispatched him to the Soviet Union, where he was captured by the KGB. But after months of solitary confinement in Moscow's notorious Lubyianka prison, Cottell claims, he was finally freed in a dramatic East-West spy swap at the Berlin Wall.

Cottell's Boy's Life adventures and True Brit delivery have earned him several invitations for repeat performances and a six-figure income that should please even the most selfless secret agent. Until recently, they also attracted favorable, and even fawning, press notices: The Richmond News-Leader seemed in awe of this "real-life spy," while Gannett Westchester Newspapers reported reverentially that Cottell had "sacrificed all that was dear to him in service to crown and country."

But some of the reviews have turned sour.

The first to raise serious questions about Cottell's professed gallantry was Art Jester, a reporter for the Herald Leader, a Knight-Ridder daily in Lexington, Ky. The Herald Leader gave Cottell a glowing write-up when he spoke in Lexington in 1983, but Jester's suspicions became aroused after Cottell announced at a Lexington Rotary meeting last March that he planned to settle permanently in the Kentucky horse-breeding capital. Jester learned later that Cottell had approached the local Episcopal bishop claiming to be registered as a clergyman in Lincoln, England, and seeking registration as a priest in the Lexington diocese.

To help research Cottell's background, Jester sought assistance from reporters at the Sunday Times of London who quickly found holes in Cottell's story. Despite Britain's reputation for obsessive secrecy, most wartime intelligence heroes today are not only officially recognized, but celebrated and publicly honored. Yet no one was willing, on the British government's behalf, to verify any of Cottell's claims.

Cottell's birth certificate, obtained from British government files, shows he was named John Harry Lansdown Cottell rather than Edward Cottell, as he now calls himself, and is not 61 years old, as he claims, but 59.

His father, 82-year-old Tom Cottell of Skegness, England, said his son changed his middle name because of his secret work for the British Ministry of Defense. But the Defense Ministry said the only Col. John Edward Cottell on its books was born in 1910, 10 years before Cottell the lecturer.

The Ministry also said it had no record of the various decorations Cottell claims to have earned, including the Military Cross (MC), Membership of the Victorian Order (MVO) and Membership of the Order of the British Empire (MBE). Cottell has also claimed to be a member of something called the Association of Descendants of Knights of the Garter, but at Windsor Castle, where the records of the Order of the Garter (an honor society for British politicians) are kept, a spokesman said: "He's a friend of St. Georges Chapel. Anyone can join that for 2 pounds a year."

Cottell's priestly credentials also proved dubious. The office of the bishop of Lincoln in England said it had no record of Cottell, and Episcopal Church headquarters in New York said likewise. Cottell's family said they saw him take part in a church service near his home in Connecticut wearing a clerical collar. But Arthur Walmsley, the Episcopal bishop of Connecticut, issued a statement saying, "Cottell has no connection with this diocese and we believe him to be a fraud."

Perhaps the most damaging comments of all came from Cottell's supposed admirers and friends in British intelligence.

"I'm getting fairly irritated by this man," said author and former agent John le Carre'. "I've never heard of him and there's no question of him being the basis of characters in my work. He is either mad or he is a fraud." And former British agent Greville Wynne commented, "Never heard of him . . . although he seems to be doing well out of name dropping."

The booking agent who sold Cottell to the chicken-salad circuit is Keedick's Lecture Bureau, of Westport, Conn., one of the country's oldest lecture-circuit agencies, founded in 1907.

The Keedick bureau, currently run by the founder's son, Robert Keedick, is known among other lecture-bureau operators as a respectable but somewhat dowdy agency that recently has lost business to more aggressive competitors. But in a promotion recently circulated to student union program chairmen at universities around the United States, Keedick lists a number of celebrity clients, including writers Gore Vidal and Norman Cousins, movie stars Ginger Rogers and Olivia de Havilland, social columnist Suzy and socialite Lee Radziwill. Also listed as Keedick clients are an assortment of well-known television and newspaper journalists.

In a telephone interview a few weeks ago from his office in Westport, Keedick said Cottell was a popular speaker and had fulfilled "quite a few" bookings at $2,500 per lecture. Keedick said he had been introduced to Cottell by a reputable New York literary agent, and that Cottell had produced documents that seemed to back up his story.

The documents, which Keedick made available to reporters, turned out to be principally undated newspaper clippings and pictures of Cottell in formal dress with others similarly attired.

Keedick said he had no reason to question Cottell's credentials, since he had recently witnessed a conversation between Cottell and a British government official at a New York luncheon, during which the two men seemed to know each other and traded stories.

Alan Huckle, the British official in question, acknowledged talking to Cottell, and said the lecturer seemed knowledgeable about Maurice Oldfield, the fabled former head of MI-6. But Huckle said he had never met Cottell previously and could not vouch for his bona fides as a hero.

Despite such disclaimers from Britain, many of Cottell's American acquaintances remain fiercely loyal to him. Curtis Thomas, a retired college professor who met Cottell on vacation in Corfu, Greece, several years ago and later shared his Manhattan apartment with him, said he would expect the British government to deny Cottell's story if Cottell really is the secret agent he claims to be.

William Kelly, a pharmaceutical wholesaler who met Cottell on a cruise two years ago and later invited him to Lexington, said he knew Cottell would be denounced by other spies.

"Anyone with the intelligence service (of) Great Britain will deny the connection," he said.

Cottell, however, is certainly maintaining his persona. At a lecture to the High Point (N.C.) Literary League in April, several days after newspaper stories apeared in London and Kentucky labeling him a fraud, Cottell received a standing ovation after concluding his standard speech. Then, as the audience milled around the room, he proceeded to autograph copies of le Carre''s novels.

In a brief, strained telephone interview recently Cottell suggested that the negative articles about him were a plot by "left-wing media . . . intent on doing me in.

"The more I defend myself, the more vicious the opposition becomes. All I can say is that all my life I've conducted myself with honor and nobody can say otherwise. Of all the people I've ever known over the many years, nobody can say I've done them any harm."