It is only social housing formerly known as council houses that is involved. For instance, if you are a single person living in a 3 bedroom house you will either have to pay extra rent or let out the two spare bedrooms to lodgers. It is designed, in my opinion to force out single people living in bigger houses than they really need into single bedroom flats or if there is such a thing available, one bedroom houses. Not very nice if you have lived in that house all your life and brought up a family of children, all of whom have moved out. I suppose there is reason for it if you consider the amount of people now waiting for somewhere a bit decent to live, but there you are - if you live in a tied house you must be prepared to have to leave it at some time, and as long as they provide you with an alternative place to live, there does not seem to be much you can do about it.