Big School, BBC One, review A good TV sitcom could leave you with various emotions: hilarity, buoyancy, even bleakness (who can forget the bitter laughter of Getting On?). But it should not leave you feeling faintly repelled, a little offended and short-changed by the lack of laughs. Sadly, Big School (BBC One, Friday) did just that. On paper, it all looked promising. The all-star cast included David Walliams (Little Britain), Catherine Tate, Philip Glenister (Life on Mars), Frances de la Tour (Rising Damp), and Joanna Scanlan (The Thick of It). They all played teachers in a grimy comprehensive called Greybridge; a bit tired, perhaps, the school thing, but surely a straightforward setting for a sitcom. Feed these variables into a space-going Japanese-made scriptwriting robot, even, and something better-than-mediocre would be produced. Remember, by the way, that joke about the first passenger flight to the moon? In which the captain's voice comes over the loudspeaker and says, "this is a state-of-the-art rocketship. Nothing can possibly go wrong, go wrong, go wrong, go... wrong... g... o... w... fzxctszx"? Basically it was rather like that. To be fair, the opening scene was delightful. Walliams's character, Mr Church, the deputy head of science, was setting up an experiment in class in which ping-pong balls would explode all over the classroom, in an effort to engage the children. Then the bell rang, and the pupils immediately scarpered; when the ping-pong balls exploded, he was the only one left to witness it. The comic pathos was perfectly pitched. So far, space robot done good. But when Catherine Tate's Miss Postern, the new French teacher, arrived, it gradually got somewhat unsavoury. The gauche Mr Church became infatuated, as did the PE teacher Trevor Gunn (Glenister), who rather alarmingly said he intended to "ruin that" and "slip her a length." This signalled a decline into an unfunny portrayal of sexual harassment which would resonate with nobody but Liberal Democrat apparatchiks. There was a quite jaw-dropping scene in which Gunn gave Miss Postern a sports massage, and she noticed that he had an erection. "It'll go down eventually," he said, casually. Either that or I'll put it in the fridge. This did not feel like good old-fashioned bawdiness, or Joe Orton-style ribaldry. It did not even feel like "edginess." This was nastiness. The climax involved Mr Church locking Miss Postern in his car. She tried to escape through the window, whereupon he and Mr Gunn dived at her, resulting in a good deal of manhandling. Now, I don't want to be over-sensitive or a spoilsport or anything, or bang on about, er, misogyny. Let's just put it this way: amusing it was not. Mission aborted.