THE HERO OR protagonist of many a suspense novel is often an outsider cut off from the normal ho-hummery of everyday existence by either bad luck or misadventure. In this trio of novels by two British authors and one American, the familiar pattern is rewoven yet again - skilfully in two instances - irritatingly so in the other.

Talk to Me About Endland by Paul Ferris is an exceedingly well-written book, brilliant in spots, which concerns the return to Britain of Francis Jarre, a former British foreign correspondent, who has just spent four years in a Warsaw hoosegow, charged with espionage.

Jarre was never much more than casual labor for the British intelligence agency that ran him in Poland and when he returns, Whitehall gives him little more than a limp handshake and a murmured "well done". Although Jarre has had some vague notion of making new career for himself in the spy trade, he quickly disabused of this and sets off to see whether he can pick up the threads of his old life as a journalist.

But because of his much publicized conviction as a spy, Fleet Street is also closed to him. Then, too, there is Jarre's marriage, which is faltering in large part because of his four-year absence. Jarre's wife is the sister of Sir Charles Helme, one of England's civil service mandarins, who counsels his sister to have patience and outwardly is solicitous toward his embittered brother-in-law.

"There is no end to their arrogance," Jarre thinks after one of his many official brushoffs. "They used and they discarded; the State's end justified the State's means. That round, bland face was off on other business. I'm never far away - the voice in the dark, the ex-directory numbers, the addresses you couldn't write to, the job that didn't exist, the man who wasn't there until it suited him, and then it was only 'hello' and 'goodbye' and the lift creaking down to the street . . . What was the point?"

But the point is that Jarre feels he has been betrayed by his country, an England he no longer recognizes or understands. The four years he spent in the Polish jail were the same years that saw the Arab invasion of England after the 1973 oil embargo. Author Ferris draws a witty, graphic portrait of the changed England that awaits his exile's return.

Just what Jarre does to get "a bit of his own back" comprises the bulk of this fine novel. It's good, solid espionage stuff with a final, fully satisfying twist.

Slave Trade by Herbert Gold features Sid Kasdan, one of the most morose private eyes in recent memory. Kasdan's wife has left him, his investigator's license has been revoked, he's broke, he's getting old, and sometimes, when nothing else is convenient, he broods about his big toe, or at least the part of it that got shot off in Korea.

When Kasdan comes home one night to his San Francisco dwelling, cutely labeled "Poorman's Cottage," he finds a half-nude mute girl bound to a chair. This is Kasdan's introduction to the sinister Worthington family, which subsequently becomes his employer as well as his nemesis.

The Worthingtons, he learns, are the proprietors of a prospering slave trade that operates out of Haiti. For a price, a very large price, the Worthingtons supply rich, aging businessmen throughout the world with young supple Haitian boys. They want Kasdan to deliver the goods. Why Kasdan? Well, because he speaks French. And where did he learn his French?

"I learned my mediocre French with the French army in Viet Nam. They still called it Indochine. It was the next best thing to joining the Foreign Legion for a crazy kid after Korea. I'm sure you know that."

Kasdan. however, is still in the dark about what the Worthingtons really want him to do. But he nevertheless flies off to Paris and there, without much fuss, picks up his first young Haitian and delivers him to a lecherous Frankfurt manufacturer.

Kasdan manages to rationalize his new and unsavory career by telling himself that "the boys are better off here or anywhere but in Haiti . . . , they'll go back after awhile to their villiage sweethearts with some European shirts and shaving lotion and some American dollars; even their parents are happy."

But his rationalizing soon falters. After his next delivery of a young Haitian to a Palm Springs client, Kasdan had a change of heart, rescues the youth, and drives across the entire United States on back roads to Miami where he hopes to embark for Haiti with his none-too-grateful rescuee. What happens next is the novel's none-too-satisfying rather murky conclusion.

Gold writes well enough when he really wants to. Unfortunately, the style that he has adopted for this book, a kind of San Francisco flip, is relentless and ultimately wearying. And his hero's continuous maundering over his lost wife, lost youth, lost chances and lost toe really doesn't help matters much.

If there is ever an award for the all-time British pro in the suspense field, one of the prime candidates should be Victor Canning whose latest novel, Birdcage , is fully up to his usual standard, which is a very high standard indeed.

A young nun, convinced that she is pregnant, decides to end it all by casting herself into the sea off the coast of Portugal. She is rescued by an Englishman, a likeable, fortyish ne'er-do-well, who nurses her back to health and sanity. She learns that her pregnancy was as hystrifal one and becomes mildly obsesses with rewarding her rescuer.

The likeable Englishman discovers that the young woman's dead mother, the flamboyant Lady Jean, suspecting that her daughter might well leap over the convent wall some day, has left her a package that contains a diary - the contents of which could well ruin a villainous, very rich English lord who wants to cap his career by being posted to Washington as ambassador.

Enter Birdcage, Canning's sobriquet for British intelligence, whose headquarters he places near Birdcage Walk. The intelligence higher-ups don't want the English lord anywhere near Washington because of his previous transgressions - which only the late Lady Jean's diary can prove. Birdcage, of course, is determined to get the diary and the chilling methods it employs to do so should satisfy even the most discriminating espionage buff. One of Channing's best.