THE truth, the whole truth and nothing but the naked truth,'' proclaims host Robin Leach of his two-hour special Madonna Exposed (Pearl 9.30pm), the show ''Madonna tried to stop the world from watching''. Far be it from us to be cynical, but Leach's propensity for gushing superlatives at the drop of a designer hat on his gut-wrenching monument to bad taste, Lifestyles of the Rich and Famous, must leave some doubt as to just how controversial this is goingto be. Even his statement that Madonna didn't want the show made rings false since her creed is ''there's no such thing as bad publicity''. Still, Leach promises an exclusive of Madonna's first demo tape, and a talk with Penthouse publisher Bob Guccione who will share secrets on never-before-published nude Madonna photos. Given that Madonna has willingly revealed all left, right and centre in her own book Sex, is this really something to get excited about? TRACE the reggae vibe as Rajan Datar and Magenta de Vine take Rough Guide to the World's Islands (Pearl 8.30pm) to Jamaica, mon. They examine those reggae roots from Bob Marley's Trenchtown house through the Dancehall slack (sexually-explicit lyrics) style and the Frontline Street Party. Learn about rural thieves, who think big and steal whole fields of crops, meet street hagglers in Montego Bay and go on a tour of Jamaica's sin city, Negril, in the company of a ''rent-a-dread'' gigolo. Stop press; Magenta finally removed those shades last week, and revealed . . . a pair of spectacles. JENNIFER O'Neill stars in Committed (World 9.30pm, ORT 101 mins) as a nurse who takes up a job in a psychiatric home only to find herself a prisoner. The hospital's director Quilley (William Windom) tells her his therapeutic approach is to allow patients to act out their fantasies on the assumption they'll discard their psychoses when they no longer have need of them. He then tells O'Neill it's fine for her to fantasise about being a nurse and she discovers she's unwittingly committed herself as a patient. One Flew Over the Cuckoo's Nest it ain't. THAT commuters' nightmare, the Tuen Mun Road is the subject of Hongkong Connection (Pearl 7.20pm). The road was built to accommodate the tens of thousands of residents of Tuen Mun New Town who commute to the city and back each day, but congestion on the highway has become the stuff of legend. The programme speaks to commuters about their plight, which is worsened with the necessity of frequent repairs to the road and its congestion caused by the many container vehicles using it. FANS of the classic sitcom Taxi (Pearl 12.30am) are reminded that the second-part of Scenskees From A Marriage, the episode begun on Monday night, is on today. Latka (Andy Kaufman) has been unfaithful with a female cabbie, and under traditional law, Simka (Carol Kane) must decide which of his driver buddies she wishes to sleep with to annul his sin.