When the curtain rose on Madonna's Girlie Show Tour, revealing a topless female acrobat sliding down a pole, the guys went wild. A mere two minutes into her first song, Erotica, as two male dancers peeled off Madonna's jacket, leaving her clad in bra and spangly hot pants, they went even wilder, screaming ''Get 'em off'' at the adored one. Madonna had promised a ''two-hour extravaganza of cabaret, humour, sophisticated choreography and Broadway production values'', but as she writhed on a revolving stage, bullwhip in hand, it looked more like a lurid peepshow. After Sex, the book, would we be treated to Porn, the concert? As it turned out, this was the only near-nudity in the show, although not, of course, the only sexual titillation. Almost all the dance routines settled down into grunt and grind, caress and fondle, and when she touched male buttocks during Fever, the audience erupted. There was simulated oral sex, group spanking, Dionysian orgiastic frolics and oodles of homo-erotica. During one of her costume changes, the male dancers fought a mock dance battle to a Madonna fantasy story about ''The Beast''. Otherwise, the setting and Broadway styling led to a succession of well-choreographed, unrelated scenarios which often seemed plain ridiculous. Why, for example, perform Holiday in military greatcoats, even if they did have a candy-striped lining? Frequently the scenario seemed to take over from the song. Take Justify My Love, for example. Set in a glorious black and white chequered box, the dancers and Madonna wore gorgeous, richly detailed court clothes. It was a marvellous image, but the scene never took off, except for more grunting and grinding, and the obligatory model stroll along a catwalk. The whole thing looked tailor-made for a video, not a live performance in front of 70,000. La Isla Bonita seemed like a return to basics. Madonna, dressed in a stripey matelot top, used a microphone stand rather than a radio mike or headset. Besides mamboing with the dancers, she also flirted with a guitarist, about the only time any musician was revealed. It was a great pity, as the musicianship was excellent throughout and perhaps deserved a little more credit. Express Yourself was the high point, transformed as it was into a '70s groove with synthesisers and wah-wah guitars. Right in the middle of the show, up went the curtain, revealing Madonna in top hat and tails, doing her best Marlene Dietrich impression. Off she launched into Like A Virgin. No, not how you remember it, but in a slow, heavily German accent - Und Like a Wi-irgin - like a second-rate club cabaret, unfunny, unmusical, and uninteresting. It was yet another example of Madonna's limited acting ability. The show never really engaged the audience. Wembley is a vast, unfriendly venue, even when packed with 70,000 ecstatic fans. It takes a big show to involve the audience, and Madonna just did not provide enough of the right elements. It wasn't until three quarters of the way through the show that Madonna asked the crowd to clap along, and then she only managed to maintain it for 30 seconds. During the encore, when she encouraged them to ''dance and sing, get up and do your thing'', only fans within eye contact range joined in. Otherwise, the adoring thousands remained pretty motionless throughout.