From April, if you live in social housing and have a spare bedroom, you will have to either downsize or face a cut in your benefits: A reduction of 14% if you have one spare bedroom, or 25% if you have two or more spare bedrooms.
An estimated 660,000 social housing tenants will be affected, according to the National Housing Federation.
They include disabled people, divorced parents, foster carers, parents with children in the armed forces and those at university.
It is causing widespread anger, anxiety and worry.
I went to meet Lisa and Brett who live in a two bedroom house in Essex.
Lisa has cerebral palsy. Brett is her partner as well as her full-time carer.
Because of her condition, Lisa spasms and moves around a lot in the night. Brett sleeps in the second bedroom 90% of the time.
Because they are a couple, they are expected to share a room. Come April, they will have to pay £80 a month for it.
They say they will struggle to pay because they simply can't downsize.
The couple are feeling the burden of the that financial pressure. Lisa told me:
We get more migraines because of the worry. We have to use some of our emergency hours to get carers in to be with me while he's [Brett] not well.
But it is not only disabled people who will be affected.
I also went to meet Alex Milne who lives in a two bedroom flat in Irvine, near Glasgow.
He is separated from his partner and his two children - Rhiann,10, and Billy, 3 - come to stay every weekend and on the holidays.
Because Alex' children do not live there all the time, the second bedroom, where Rhiann sleeps, is deemed spare.
He has been told he must downsize or pay £40 a month and since he is unemployed and on jobseeker's allowance, he says he will have to cut down on food to afford the added cost.
Even if he wanted to downsize, he may not be able to since there is a huge shortage of one bedroom properties in Scotland.