Campaigners are upping the ante based on no clear definition and it being up to Local Authority HB teams to interpret what a bedroom is. The 1985 Housing Act offers a solution for some, outlining that anything under 50sq feet is not to be counted as a room someone could be expected to sleep in, and anything under 70sq feet should only be for 0.5 of a person ( a child under 10 in layman's terms), but for others the space standards in the act relate to the whole property.
The reality is the courts will have to decide, and this considered article in Politics Worldwide by an anonymous policy specialist sums up the position quite clearly.
In practice there can be no doubt that housing organisations can expect challenges on the number of bedrooms a property actually has - particularly converted properties, and potentially even small newer build homes. Knowsley Housing Trust acknowledged this and has reclassified properties. If you’re one of 90% of the organisation’s which hasn't, best get the tape measures out to be ready for the challenges which will come. Unscrupulous solicitors will no doubt be targeting whole areas and neighbourhoods on a no win no fee basis if no definition or guidance is forthcoming from the DWP soon.