Momentum has always been a grassroots organization. Formed in 2015 with a mandate to protect a Jeremy Corbyn leadership from a parliamentary party eager to depose him, the group has always represented the left of the Labour Party membership base, and agitated for more democracy within the party.

A core Momentum strength is its volunteer-run canvassing drives, and in the 2017 general election, Momentum helped send out activists to marginal seats all over the country. That year, Corbyn increased Labour’s vote share more than any of the party’s leaders since 1945 — destroying Theresa May’s majority in the process.

Now, with another general election around the corner, Momentum is spearheading the campaign to send volunteers to doorsteps across the country. To learn more about the organization’s campaign strategy, Alex Doherty of the Tribune podcast, Politics Theory Other, spoke to Momentum co-founder Emma Rees. In the summer of 2015, Emma volunteered with Jeremy Corbyn’s leadership campaign during her summer break as a primary-school teacher. Just four weeks after his victory, she became one of the three staff members who helped to establish and build Momentum from the ground up, to a volunteer-driven, membership organization of over 42,000 paying members. Rees continues to support Momentum, and now also works for The Social Practice, alongside veterans from the Bernie Sanders 2016 campaign.