After the burger becomes boring, what next? Which cuisine will be the next to be endlessly re-created in high- and low-brow versions, in street food vans and in trendy pop-ups? Perhaps the answer lies in the humble burrito. London's Mexican food scene has made a slow, steady march toward authenticity and the same bright, vibrant and strong flavours you'd find in D.F. Wahaca has rapidly expanded from one to nine restaurants across London, lunch favourites Benito's Hat have made an impression with the work crowd with their branches between Goodge Street and the Strand, and now Lupita, Chilango and major U.S. chain Chipotle are muscling in. Even the street-food crowd has rightly tapped into what is, essentially, street food: Leather Lane's wonderfully named Daddy Donkey street van is always busy. The latest is Poncho 8, whose co-founder Nick Troen is promising 20 outlets by 2014 according to Eat Out magazine. Let battle commence.