During and after Corbyn's leadership election, there was a large increase in the number of Labour Party members; from 201,293 on 6 May 2015 (the day before the 2015 general election) to 388,407 on 10 January 2016. Local Labour constituency offices have attributed this rise mainly to the "Corbyn effect". Reflecting an increased interest among the young, university cities and towns recorded some of the biggest rises. Following Corbyn's election as Leader of the Labour Party, Bath's Labour Party membership increased from 300 to 1,322 and Colchester's from 200–250 to 1,000. Momentum, a grassroots movement supportive of Corbyn and the Labour Party, has (as of 2019) about 40,000 members. Following the EU membership referendum on 23 June 2016, and the many resignations of shadow ministers which followed, 100,000 new members joined the Labour Party, raising Labour's total membership to 503,143.