[Image stolen from The Political Scientist]
Its a pretty striking correlation. As for the why, its becoming increasingly obvious that Labour is not going to win this election, causing people to just give up on them. Beyond that, they offer nothing (other than yet more economic sadomasochism), don't know what they stand for, and look like muppets. Its entirely natural that people who favour a more equal society will give up on such a party and instead stay home: because they're not really offering one, and to the extent they are, can't deliver. But for a party which aims to reconnect with the "missing million", its exactly the wrong trend - rather than shrinking it, they look set to add to it. Heckuva job, Labour.