"Venom" makes the most of a nasty situation, mainly by deploying all-star troops to handle it. Contrary to what the TV commercials for the film imply, "Venom" is not the "Jaws" of snakes, but there is a snake in it. Lordy, lordy, a snake and a half -- nothing less than the deadly black mamba, "probably," a toxicologist avers in the movie, "the most poisonous snake in the world." When this baby rears back and opens its amazingly huge mouth, it is excruciatingly intimidating. Mamba mia, that's a snake!

Early in the film -- which opens today at area theaters -- the snake takes up residence in a cushy London town house where a trio of miscreants is trying to kidnap an asthmatic 10-year-old boy. Those not averse to movies involving a See VENOM, D4,Col. 1 VENOM, From D1 snake, kidnapers and an asthmatic 10-year-old boy will find "Venom" tense and well-acted, a smooth-running model of slightly fiendish British efficiency.

The credit goes not only to the snake, who truly is an unholy terror, but also to director Piers Haggard, who took over from Tobe "Chainsaw Massacre" Hooper just before shooting began, and Robert Carrington, who wrote a crisp, cunning and streamlined screenplay that recalls such other examples of elevated genre films from England as "The Day the Earth Caught Fire" and, more recently, Richard Lester's "Juggernaut."

Haggard and Carrington transcend some of the limitations of the form with the help of big-league acting talent from the British reserves: Nicol Williamson as police commander William "The Bull" Bulloch; Oliver Reed as the most thuggishly unsavory of the kidnapers; Sarah Miles as the believably plucky toxicologist; and Susan George as one of the snake's hors d'oeuvres.

In addition, America's own Sterling Hayden has a geezer's field day as the kidnaped boy's grandfather, a wily retired hunter in whom the lad (Lance Holcomb) has a natural spiritual ally. The overexposed but unfailingly menacing Klaus Kinski plays the criminal mastermind. Rita Webb, who pops up often on the imported "Benny Hill Show" in frumpy dowager roles, has a brief spot as Mrs. Lowenthal, the dangerously confused wife of a pet store owner; and Mike Gwilym, seen on public TV here last year as the jockey-detective in "The Racing Game," plays a hale cop. Late in the film, Miles advises, "You'd best get hold of David Ball," a reference to the film's technical adviser, the reptile keeper at the London Zoo, and who should show up as Ball but Michael Gough, veteran of innumerable films from that lively, blood-drenched Hammer era of British horror filmmaking.

The highest praise that can be heaped upon a thriller remains the adjective "Hitchcockian" (although Mr. Hitchcock himself once said he preferred to read "not as good as"); "Venom" is one of the few films that really deserves the comparison, and not because of De Palmian self-conscious references (although the little boy riding in a cab with the deadly snake in a box on his lap does recall the lad with the bomb in "Sabotage") but because the suspense is cleverly and methodically sustained, and the characters have more grit and dimension than the usual movie victims and victimizers.

Thus the movie may not satisfy the "Halloween" crowd -- it lacks splash and gore and doesn't deserve the Motion Picture Association of America's capriciously applied "R" rating -- but succeeds at bringing an audience to that vaunted locale, the edge of its seat. Haggard, who directed the original BBC-TV series version of "Pennies From Heaven," pulls a viewer in from the earliest scene, and Carrington's screenplay (from a novel by Alan Scholefield) tumbles out the exposition with dizzying swiftness, each succeeding detail canceling out whatever incredulity is hanging around.

A more spectacularly ghastly finale was probably in order; there is no particular evidence of refined movie technology, though that's almost refreshing after so many horror movies that were mere high-tech fits. The movie is not about the snake -- it's about venomousness generally, and the poisonous creatures that exist within all species -- but Haggard keeps the snake uppermost in the mind with cuts to effective snake's-point-of-view shots. The theory here is that waiting for something to jump out at you is a more pleasurably dreadful sensation than merely being pelted with shrieky scares; "Venom" proves indubitably and unnervingly that the theory is correct.