Where I live, the Labour Council and the MP have huge majorities, so tactical voting is pointless.
I was talking to a Labour Councillor at the weekend and he had an interesting theory. It could be the ramblings of a desperate man, but he reckoned Labour voters didn't bother voting last time because it was obvious Labour would win. This time, with the prospect of the Conservative's winning, more Labour voters would turn out.
I was doubtful, but he did cite a local example. The BNP finished second in a local ward and were a couple of hundred short of the Labour winner. That councillor died and a local bye-election was called. The BNP thought they could win it and canvassed very hard and spent a lot of resources and man hours in the ward. The result is that Labour increased its majority by 400. The stay at home Labour voters turned out in the bye-election to keep the BNP out.
Will Labour voters who didn't bother to turn out at the General Election because they knew the Tories couldn't win it, turn out this time because they know the Tories might? It is an interesting theory.