how many government/state owned beds there are in the UK currently empty? What I mean by that is this.
Locally there are hundreds of beds/bedrooms empty in the garrisons. These could be used for the homeless, illegal immigrants waiting to be shipped out the country, being army garrisons the security is in place to use them for a temporary (or even permanent) prison. I am sure there are many more categories of people needing accommodation who could use these facilties of which there must be hundreds around the country. Flood victims for one.

This has not taken into account Buck House, Windsor Castle, empty office blocks that can be used to offset tax for big corporations.