There’s also a barge, a van, a locomotive and a sporty red roadster. Toad, one of literature’s first motormaniacs, can’t resist joyriding in somebody else’s car and he winds up in jail. This leads to the political dimension of the story as his estate, Toad Hall, is taken over by a rabble of weasels, stoats and ferrets. For kids these squatters are just mean slobs, but for Grahame they embodied his fear of the forces of anarchy and revolution. Alan Bennett gives these furry Bolsheviks a nice contemporary twist: his weasels plan to turn Toad Hall into a leisure center.

Bennett handles such touches with a lightness that adds to the fun for wised-up adults and doesn’t spoil it for kids. A self-styled “old-fashioned liberal,” Bennett nonetheless has great affection for the conservative Grahame’s utopian fantasy that embraces the old, pastoral England and rejects the smoke and stress of the modern world.

Michael Bryant, one of planet Earth’s best character actors, plays Badger as the ultimate squire, oozing benevolent authority from his velvet collar to his cheeked spats. Richard Briers’s Rat has the blazer and the bearing of a naval officer (he is, after all, a water rat). David Bomber’s Mole is an eager, duffel-coated north-of-England schoolboy, and Griff Rhys Jones brings a goon-show bluster to his Toad, a low-calorie Falstaff in bilious green plad knickers.

Richard Eyre, director of the National Theatre, at first wanted Bennett to write a play that would weave together Grahame’s life and his masterpiece. “But I couldn’t do it,” says Bennett. “His life was a terrible story. His mother died when he was 5. His dad was an alcoholic. He had a troubled marriage and his son, Alastair, was born blind in one eye and committed suicide at 20 by lying across a railway track.”

Bennett, a butcher’s son, never read “Wind in the Willows” as a child. Books like that or “Alice in Wonderland” looked too “forbidding” in their leather bindings at the local library. “I’d say, ‘That looks like a classic, so I’m not going to read it’.” Instead he read comics. But he grew up to go to Oxford and became one of the four university wits - the others were Jonathan Miller, Dudley Moore and Peter Cook whose satirical revue “Beyond the Fringe” in the early ’60s changed the shape of comedy on both sides of the Atlantic.

Bennett, the least famous of the four, is arguably the most gifted as actor, comic, director and prolific author of plays (“Single Spies”), TV drama (“Talking Heads”) and movies (“Prick Up Your Ears”). Once, at a dinner with Prime Minister Harold Wilson, Bennett identified himself as one of the “Fringe” men. The P.M. looked at him sternly and said: “I don’t remember you. You weren’t one of the original four.” Bennett felt, he said, “like Trotsky when he was cut out of the history of the revolution.” If “Wind in the Willows” comes to the United States (producers, including Lorne Michaels of “Saturday Night Live,” have made inquiries), Bennett will get the international fame that has so far eluded him.