Arthur Figgis wrote:

I know it is one of those things that "everyone knows", but has anyone
ever looked into to the extent of this? Are there huge numbers of flats
which could lower general property prices/reduce commuting/house the
homeless/facilitate more immigration (delete accoording to taste), or it
it one of those things which someone once suggested and it just stuck?

And of course ignores the benefits of unoccupied flats - i.e. although they
still pay council tax on the full value of the property, they create zero
polution or congestion and make no demand on services. I supose this is somewhat
offset by the fact that they aren't spending any money in the area either.