Performance poetry, I am told, is the new rock ’n’ roll. Poetry nights may vie with comedy at venues up and down the country, and a new generation of twentysomething urban poets and rappers are certainly strutting their stuff, but I’m yet to be convinced that it’s the burgeoning success that promoters would have us believe. Still, the first of two Pop-Up Poetry evenings of “poetry stand-up style” in the upturned purple cow on London’s South Bank gave me a chance to sample some of the artform’s best-known performers, and it confirmed my view that it’s a very mixed bag in terms of style, content and quality.