Well what a fantastic result for mr.gulad..suspended sentence! What a deterrent . What's needed is photos of tenants on file, and tenants either to visit the housing office and sign every year, or have staff visit them and check. If any one complains it would arouse suspicion. With people needing housing it's criminal that some low life should make a profit by charging rent for property that he doesn't own.
They do have photo ID of tenants on file now Jan - not sure how many but I am and I've been a council tenant since 1972. Also my housing officer calls round occasionally to check that it's me living here. I've seen via the media etc that Southwark Council have had a degree of success in weeding out illegal tenants.