The surge in Green party membership is big political news at the moment, chiming with the continuing debate about whether the party’s leader, Natalie Bennett, should be invited to participate in the proposed leaders’ debates.

Questions around whether the Greens are a major party are predicated to an extent on questions about who their members are and whether their increased membership will translate into an increased vote share. We can, of course, also ask legitimate questions about the trustworthiness of their membership figures, though this can be said of any political party.

Broadly speaking, the Greens’ membership is split into two main groups: the green and red wings. The former group tends to be made up of older members who have a historical commitment to conservation and green campaigning, but are not necessarily left-leaning. The latter group tends to be the younger members, who are also committed environmentalists but combine this with a broader leftwing political philosophy.

The importance of the latter group can be seen in the leadership’s emphasis on issues of equality and fairness alongside traditional green principles.

Our polling at YouGov suggests the new members of the party are likely to be younger people, as we have seen a steady increase in support for the Greens among this group. This has put the party on the same level of support (22% say they would vote for them) as the Conservatives (second only to Labour) among 18- to 24-year-olds.

Support for the party also comes disproportionately from among the middle class and those with higher levels of education. What is clear from the figures is that those who support the Greens are more likely to take the step of joining the party. This is shown by the fact that while the percentage of those saying they would vote Green at the general election has stayed at around 8%, their party membership has been steadily increasing. So they’re getting more members from a smaller group of supporters than Ukip are.

This last point suggests that increased party membership does not necessarily translate into increased support at the polls. This is in part because party members tend to be an unrepresentative bunch; there is a very small number of people in the population who care enough about a party to join it. In fact, the context for the rise in membership for the Greens is a broader decline in political party membership over the past 50 years.

There is one way in which increased party membership may help the Greens at the general election: that’s more “boots on the ground”. While it is by no means the whole story, a well-run grassroots campaign can make a difference on polling day.

Assuming such an impact, having a big leap in people who are willing to door-knock, distribute flyers and talk to the public on behalf of the party can only help. It also means the party has a larger group of supporters who are willing to be vocal on issues such as the inclusion of Bennett in the leaders’ debates.

So increasing membership for the Greens is good news for the party as it gives them a big group of committed, young, educated campaigners to get the party’s messages out there. There is, though, no guarantee that this will translate into an increase in support on 6 May.