Another idea that has been worked on is taxing benefits. Official Treasury numbers seen by Newsnight show that taxing child benefit would raise £1.5bn, taxing DLA £800m and if you taxed the Winter Fuel Payment (which Vince Cable advocated on Thursday), you would raise £200m.
But the trouble with this is that the Treasury hate it. They point out that it would pull huge numbers of people into self-assessment, making it very messy administratively and politically. The Inland Revenue would probably have to hire 5,000 extra staff to deal with the extra work. But it is £2.5bn and every penny counts.
How desperate do you have to be to consider such an obviously insane idea?