Visions of buying up blocks of flats for £200 Million, all MPs living in the same place, security implications etc etc are conjured up.
In fact, none of that needs to apply. The solution is very simple.
Take Portia Filly-Funkler the new MP for Stackton-Trestle who is elected for the Peoples Party in 2010. She chooses a flat for sale on the open market in Southwark and has this flat approved by the Government as a suitable one for MPs. The government buys the flat with a mortgage and pays the mortgage installments directly to the mortgage holder (paying partly what it would have paid under the current scheme anyway, but in this case the state has the benefit of owning the property when the mortgage is paid off). The government also provides an inventory of basic furnishings for the flat from a central repository of furnishings bought in bulk at auctions and the like, therefore getting them at a good price for the taxpayer.
Portia moves into her flat and signs for the basic inventory of furnishings. She is responsible for replacing any breakages, but the government periodically agrees to replace worn furniture with replacements from the central repository. Portia adds a few little touches to the property at her own cost, such as some lovely pink frilly scatter cushions she bought in a lovely little shop in Stackton Trestle.
During her term in parliament, Portia receives no expenses whatsoever for her second home. She pays for food, soap etc herself, and she would do if she was living at her main home in Stackton-Trestle.
Dear old Portia is then swept from her seat by the Stackton-Trestle Revolutionary party in 2014.
The key of the flat is then handed on to a victorious new MP under the same process.