The study, by the University of Edinburgh and the UK Medical Research Council and published in the journal Intelligence, indicates that childhood IQ is as important as social class in determining political allegiance. The IQs of more than 6,000 subjects were recorded at the age of 10, before any secondary schooling. Twenty-four years later they were asked about their voting habits.
Mean age 10 IQ scores for people voting in the 2001 general election for various parties were as follows: Green 108.3; Liberal Democrat 108.2; Conservative 103.7; Labour 103.0; Plaid Cymru 102.5; Scottish National 102.2, UK Independent 101.1, British National 98.4; Did not vote/None 99.7. See more here.
I do also remember research a long while ago that found more degrees, doctorates and profs per member in the Green party than any other party - of course that could lead to accusations of being out of touch and ivory towers....
But will voting Green make you more intelligent?!