Volunteers were taught how to do “persuasion canvassing”. This is a technique that uses a “response cycle” – empathising with a voter’s concerns on the doorstep, isolating the main thing they are worried about, and then giving relevant information about your candidate to address those concerns. It sounds quite basic, but lots of first-time doorknockers would overload voters with non-specific information about Labour’s manifesto, or end up in a confrontation with people they didn’t agree with, for example on Corbyn’s leadership. “It’s really overwhelming and kind of in your face, right?” says Parkin. “So one of the things I worked on at first was acknowledging concerns and building empathy. That’s a big thing of what I do.”

This is a shift from Labour’s time-honoured Voter ID method, which Parkin demonstrates sarcastically: “Knock knock. Hi! Are you voting Labour? Yes. Great, thank you! No. Great, thank you! Maybe. Great, thank you! Bye!”

Once trained, Momentum’s volunteers were sent to marginal seats no one – the Labour party included – believed were winnable. Groups of hundreds went to Croydon Central, Kensington, Canterbury, Battersea, Sheffield Hallam, Brighton Kemptown, Leeds North West, Crewe & Nantwich, Lancaster & Fleetwood, Hampstead & Kilburn, Derby North, City of Chester, and Ealing Central & Acton.

This was enhanced by the My Nearest Marginal online tool, the growing impact of which the New Statesman wrote about before the election. This provided a car pool service for participants to travel easily and cheaply to target marginal seats. You just type in your postcode, and the map shows where it’s most useful for you to go. By polling day, 100,000 people had used the site – that’s nearly a fifth of the whole of Labour’s membership, and four times that of Momentum.