Got a much better idea; how about cutting out the 300k homes, opening up all those spaces to young families who might actually eventually want to get a home, not to mention lowering the costs of rent and housing at the same time since you'll be removing the ‘floor’ that the council has established in rents. Eject everyone. If you feel bad about it, set up a tent city for them, see how long people will actually sit on their duffs and how many will suddenly find the ability to hunt for a job.
Wasn’t that part of the purpose of the “bedroom tax” they recently implemented in the UK? If you’re on welfare and living somewhere with more bedrooms than people who need them, you have to pay more or give up part of the benefits because you have excess space?