From 1 April something like 660,000 people who have spare bedrooms are going to be taxed if they don’t take in a lodger or move to a smaller house. This might sound like a selflessly even-handed if drastic move on the part of the welfare minister Lord Freud, given that his own house has eight bedrooms, some of which are presumably spare. But the tax applies only to those in social housing who receive housing benefit, not to owner-occupiers or people with two homes. It doesn’t apply to pensioners, unless they are foolish enough to have a younger partner. The government is trying to sell it as a sensible measure that simply requires some of us to shove up a bit and make room for someone else. ‘What we can’t continue to do,’ Grant Shapps says, ‘is pay for a million empty rooms whilst we’ve got… so many people in desperate need of a house at all.’

The kinds of people who will be penalised for wasting a bedroom include: a couple whose only son is in the army but stays with them when he’s on leave; a couple who sleep apart because one has a chronic illness; a person who doesn’t need a live-in carer, but has one who stays when required; a father separated from his children who has them to stay at weekends; someone who helps the parents of a disabled child by having him sleep over; a lone parent with a son and a daughter, who are expected to share a room until one of them is ten; a disabled person living independently in a house adapted to their needs.

Tenants’ benefits will be cut by either 14 per cent (for one spare room) or 25 per cent (for two). This is expected to save the Treasury £500 million, 6 per cent of which (£30 million) will be put aside for ‘exceptional cases’ exempt from the penalty. Many of the unexceptional majority will be forced to move.

There might be some cruel sense to all this if people could actually shove up a bit, as the government wants. But there simply aren’t enough right-sized houses available. Even in Hull, where housing demand is not as great as in (say) the south-east, there are 4700 affected tenants but only 73 properties for them to downsize into. The coalition is targeting social tenants in ‘subsidised’ housing, ignoring their own figures which show that while 10 per cent of social tenants under-occupy, the proportion for private tenants is 16 per cent and for owner-occupiers 49 per cent. Even more absurdly, if a single person lives alone in an eight-bedroom house, they get their council tax knocked down by a quarter to compensate them for the vast space they have to look after. In other words, under-occupation by home owners is not penalised but rewarded by, on average, £361 a year.

There are signs of revolt. The label ‘bedroom tax’ has stuck despite government objections. Glasgow advice agencies have obtained counsel’s opinion that the use to which the room is put determines the issue, so if a tenant has a room where the children do their homework it can’t count as ‘spare’. Some social landlords may forego rental income by redesignating houses as smaller than they really are. There are many local campaigns like Leeds Hands off our Homes. And a national petition has so far gleaned more than 100,000 signatures (even if it’s addressed to Cameron at ‘the House of Lords’).