Vote for the party that is, in YOUR opinion, going to do least harm !

Well, if that's sufficient, all you have to do is vote for one you are sure isn't going to get elected.
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I agree with ard macha there - I think one of the most popular things De Gaulle ever did was when he vetoed the UK joining the Common Market. Popular in France I mean.

But with all the Poles and Czechs and suchlike coming in to the country now things should start looking up, and the tone of the place might improve.