I think selling off council houses was a big mistake, I also think the idea of lifetime tenancies regardless of income and the right to pass them on is silly too.
council housing should be means tested, people should be moved (forget the bedroom tax and an encouragement just move them) if they have more bedrooms than required (of course this also means the responsibility is on the local authority so in a situation where there aren't sufficient suitable properties the tenant isn't penalised as they are with the bedroom tax)
In large urban areas, especially London, housing should be managed regionally instead of each local authority having to make provisions - there really isn't much point in giving people free accommodation in say Westminster, it is a massively inefficient use of resources to have council flats that are technically valued at close to £1 million. Most zone 1 accommodation should be sold off and more accommodation can be built elsewhere. Waiting lists can also be reduced by simply getting rid of people who don't have any hope of qualifying - currently there are plenty of chancers who already work and there is still a mentality that anyone and everyone regardless of income should have a council house if they want - that needs to stop.
Housing in Central London ought to go as a priority to key workers who can't otherwise afford to live there. The long term unemployed and the elderly should be moved further out.
I've got no sympathy whatsoever for the people who moan about social cleansing if they can't live in a very specific area of London, plenty of working people who have moved for work haven't got that luxury and it isn't feasible long term anyway as more and more people want to live in certain areas - if you're being subsidised by the rest of us then you should be happy that you're being housed in the general London area and likely still living in a flat that is more valuable than plenty of detached houses up north.