Green Party. Technically the UK does not have one Green Party, but three (with separate Green Parties in Northern Ireland and Scotland).
Nonetheless the three cooperate quite closely. The only party with seats in the European Parliament is the English and Welsh Greens however.
The Greens are fairly weak in the UK due to Britain’s political system which tends to squeeze them out, though they won a seat in the national parliament in 2010 in the politically radical seaside resort of Brighton.
The British Greens tend to lean towards a more eco-socialist style of Green ideology, leaning very obviously to the left of Labour on every issue. The party’s support tends to be drawn from academia, students and left-liberal professionals. The party’s current leader, Natalie Bennett, is a former Guardian journalist.
Like most Green parties the UK Greens were historically Eurosceptic. The party is less Europhile than other modern Green parties, however, backing a referendum on EU membership. The party’s broad stance could now be described as being neither opposed nor in favour of the EU per se but rather wishing to deal with the EU on a policy by policy basis.
The party is one of the most loyal members of the European Green Party, voting with its group 98.9% of the time, fifth in the group.