Two explosions stopped performances at the National Theatre last week. But a third has come from the imposing figure of Dame Diana Rigg, currently appearing in Humble Boy at the theatre. The great dame has launched an attack on backstage conditions, comparing the dressing rooms to "battery-hen hatches". Rigg, returning to the theatre for only the second time in its 25 year history, is clearly not a happy bunny. "It makes me cross every time I enter the building," she fumes. Every time? This can't be good for the nerves. I know actors like to treat every performance as a brand-new experience, but after the first few times, wouldn't you think you'd have a sneaking suspicion about what to expect? The National was, after all, completed 25 years ago. It's a tad late to start complaining.