It is a blustery evening in early April, and a crowd has gathered in east London’s Bethnal Green to watch a comedy show. They seem like a fairly typical audience: white, but not exclusively so; male, but not overwhelmingly. Slightly older than average, perhaps, but I still spot plenty of young couples, and even a teenager or two. But don’t be fooled. This is not your run-of-the-mill comedy night; this is Comedy Unleashed: a rebellion against the “safe, tramline orthodoxy” of the contemporary comedy circuit, according to its website, and a haven for “free-thinking comedians who leave their self-censorship button...