Just had long heated discussion with DH about this.
We live in a Labour/Conservative marginal. No one else has any remote chance of getting in. I am therefore planning to vote either Labour or Conservative as I consider my vote to be wasted if I vote for anyone else.
DH says I should vote for the person/party who I want to represent me, regardless of whether they have any chance of winning, which is what he is planning to do. He feels strongly that this is a matter of principle.
I can see both sides of the argument but obviously think he is wrong