In ‘Prime Central London’, apparently, where more than 25% of property purchases in 2013-2014 were by non-resident overseas nationals.
This map from a 2015 report by Kensington and Chelsea council shows the actual locations of long-term unoccupied housing:
The report found that the most expensive homes (those in council tax bands G & H) were more likely to be empty (i.e. unfurnished and unoccupied for more than six months).
