The Independent has published three charts that they claimed showed why British politics is so interesting at the moment (how very Buzzfeed).
One of the charts was this one showing the political party memberships:
Equally it is worth noting that the figure quoted here for the Green Party is that of just the Green Party of England and Wales. If you added the membership of the Scottish Green Party and the Green Party of Northern Ireland the chart would look something close to this:
This makes the Green Party membership comparable to that of UKIP. The Green’s membership however is growing about three times as fast in 2014 than UKIP suggesting that these positions will soon be reversed.
Read more on party political membership here.