Just as Margaret Thatcher fought a losing battle to stop the community charge being called the "poll tax" so this Government is losing the battle to stop "bedroom tax" entering the lexicon.

Officially, Ministers plan to introduce “size criteria for working age Housing Benefit claimants living in the social rented sector”.

But Labour has dubbed the proposal a “bedroom tax”, and the phrase is sticking – even though what the Government plans is a benefit cut and not a tax at all.

Ministers have decided to cut housing benefit for people in social housing who are deemed to have more bedrooms than they need, based on the size of their family.

If you have one extra room then your housing benefit will be cut by 14 per cent. If you have two or more then the cut will be 25 per cent.

You can keep your home if you can find the cash, but the idea is that many affected families or individuals will find somewhere smaller to live.

It may seem reasonable to ask why parents of grown up children who have left home should continue to live in a large family house, provided by the council or housing association (which often got their housing stock from councils in the first place), when families which actually have young children are stuck in small flats and languish on a waiting list for something bigger.

In response, Labour has highlighted exceptional cases – such as disabled people who use a spare room when a carer stays overnight.

But it seems to me that what might resonate most with voters is the sheer misery inflicted on people who are forced out of the home they’ve lived in for most of the adult lives – and where they raised their children – even if they have no disability or other special circumstances.

The National Housing Federation has produced estimates for the number of people expected to have housing benefit cut in each constituency.

In Dudley South, 1,283 households will face cuts. In Birmingham Yardley, it’s 1,325 and in Stourbridge, in the Black Country, it’s 1,108 households.

These three seats, incidentally, are marginals held by Conservative or Lib Dem MPs, which Labour hope to take at the next election.