"Stop the World -- I Want To Get Off," one of the few British musicals to become an American hit, is the fairly offbeat bill for Hayloft Dinner Theater. Its rewarding attraction is a fine performer, Richard Beneville, who puts over such solid numbers as "What Kind of Fool Am I?" and "Once in a Lifetime."

Beneville scored as the emcee in "Cabaret," which opened Hayloft in 1972, and has been too busy, evidently, to take up producer Frank E. Matthews' invitation to return. He is one of those performers with all sorts of talents who hasn't had the luck to create a major part and so, more's the pity, is relatively unknown.

But he is a performer worth watching, lithe, alert and with expressive, sharply etched features. He is the first performer I've heard in some time who gives vocal clarity to every syllable he sings or speaks. This is a rare quality, and hopefuls can learn much from how Beneville uses his well-placed baritone and speaking voice.

He is not afraid to open his mouth, to work his tongue over consonants and vowels, to let the air flow freely from lungs into larynx. This technical skill has been so firmly mastered that it is unobservable until one starts analyzing how he gets his effects.

A London success which transferred to New York in 1962, "Stop the World" then appeared to be a novelty, the tale of a chalk-faced circus clown who depicts the rise of an office boy to chairman, political power and royal honors. Anthony Newley and Leslie Bricusse called their character "Mr. Littlechap," representing the hopes and experiences of an average Briton.

Admired for its suggestion of social significance, "Stop the World" now is relatively dated, though a new version is in preparation for Sammy Davis Jr. The supporting parts are doubled as Littlechap progresses through sexual encounters with a Russian, a German and an American while his daughters produce children of their own. Sherry Caldwell has the stiff, unaccommodating role of the recurrent female.

But with Beneville's strength and skill as Mr. Littlechap, Hayloft has the right man to be on stage throughout. With "I Wanna Be Rich," "Typically English," "Gonna Build a Mountain" and the aforementioned songs, Beneville is a first-class performer who exudes just the style and aplomb to do them more than justice.