Should Labour MPs be scared of Jeremy Corbyn-supporting movement Momentum? The group says it is attempting to build on the the groundswell of support for Jeremy Corbyn. Still in its infancy it has already drawn the ire of Labour MPs and activists and sections of the press. They've been compared to the Militant Tendency that took over Liverpool Council in the early 1980's. They've been accused of aspiring to deselect disloyal MPs and have been described as a hard left rabble. Some Labour MPs are worried about their rise, but what is Momentum and what do they want? Stephen Bush of the New Statesman has been to Walthamstow, home of just one of these new groups, to find out.