The warning from Hollywood mogul Samuel Goldwyn that writers should “leave the delivery of messages to Western Union” has lost some of its impact since the company stopped sending telegrams. However, Goldwyn’s underlying message – that political issues are better left to parliaments than dramas – still has supporters not only in cinema but also theatre, where many producers, reviewers and consumers are wary of shows that openly stage a debate.Three London autumnal successes, though, make a strong case, though with very different approaches, for the theatre of ideas. The shorthand description of Hangmen might be a “play about capital punishment” but Martin McDonagh’s play, which transfers to the Wyndham’s Theatre from 1 December after a