To see the loyal opposition in action, do not go to Parliament. Instead nip two miles north-east to a nondescript office in Clerkenwell in central London, which is home to Leigh Day, a law firm. The firm itself is not a household name, but its cases are. Birmingham City Council is near bankrupt due to a series of equal-pay claims led by Leigh Day, with courts deciding that cleaners should earn the same as binmen. It has harried the government over pollution in the River Wye and, when that failed, charged after the polluters instead, launching the biggest environmental class action in British history on October 8th. When ministers complain about legal challenges delaying infrastructure projects, such as a new nuclear-power station in Suffolk, they are often pointing the finger at Leigh Day.