By Monica Poletti and James Dennison
Between 2010 and 2015, the Green Party went from being an afterthought in British politics to an established member of the second tier of Britain’s party system. Although their 2015 election result disappointed many, the “Green Surge“ in membership from late 2014 onwards turned them into the third largest party in England and Wales. Monica Poletti and James Dennison explain the surge did not alter the party’s ideological composition but instead reinforced earlier movements to the left. The Green Surge also created a more balanced membership profile in terms of gender, education and social class. But while most of the party’s members voted for the Greens, one in five of these “surgers” did not, raising questions as to the durability of their membership.
In just seven months, between October 2014 and May 2015, the Green Party’s membership increased from less than 20,000 to over 60,000. The growth is interesting not only because membership figures of all British parties had until then been in decline for decades, but also because a near overnight trebling of any party’s membership would be expected to radically change the profile of its average member. Indeed, many commentators spoke at the time of a shift in the Greens from an environmentalist stance to a leftist or even populist positioning.
Here, we explore if and how the Green Party’s membership was transformed by the Green Surge using data from the ESRC Party Members Project (PMP). Based on 845 Green members surveyed shortly after the 2015 general election, we divide these into three cohorts based on date of joining: before 2010 (12 per cent of those surveyed), between 2010-2013 (15 per cent) and the Green Surge period of 2014-2015 (73 per cent).

