Please be gentle as this is my first post on here. (Lurked for a while though!!)
I look at it like this:
The government used to pay the interest on mortgages after 39 weeks(?). Now they wont pay it for 2 years - Then they will pay it all back. In the meantime the banks aren't getting any of this money back at all. Therefore they have to go to the Government for more loans, and the Government owns a larger part of the banks. Eventually the government will own outright several of the banks. In 2 years, when they have to pay the interesdt back, they are paying it back to themselves, plus, when they repossess all the houses, (from those who couldn't pay, and are in even worse negative equity than they are now), they then own those houses and have a nice stock of council housing, much of which will still be within NHBC, so all the repairs can be done at their expense.
Just a theory