That does sound like an attractively simple solution at first glance but if I have understood your proposal correctly, I think it would fall at the first hurdle. Even the ‘ban all landlords’ Greens have private landlords among their number so the political will is very likely to be lacking.
Then you start thinking about the practicalities. Basically you are proposing to crash (or put very serious brakes onto) the property market in order to remove private landlords from the equation and then further government to buy up millions of individual properties.
Imagine the man hours involved in processing so many house purchase transactions and also guard against the very real issue of mass fraud (always a major feature in huge government financial undertakings like that). Then the admin overhead of the state becoming landlord to millions of previously private tenants (11 million people across 5 million odd properties) .
Then we have the wider financial effects involving things like pensions - both where an individual has bought rental properties as a pension and the huge pension funds that have a stake in large scale property companies etc - that needs to be dealt with.
There is no argument for turning away refugees. We can reduce illegal migration by concentrating on the statistically larger issue of people who enter legally and then overstay their VISAs.
I’m not sure that turning away actual refugees has been proposed by anyone. Obviously we need to get much better at deporting those ineligible to stay and cracking down on the widespread immigration fraud recently exposed by the BBC. We seem to be thwarted at every turn by the ‘human rights’ lawyers.
We absolutely can send all asylum seekers to a safe country, say Rwanda for example, to be processed at far lower cost than we are currently spending. We then have cheaper accommodation, a good deterrent for the economic migrants, terrorists and criminal fugitives with no risk of absconding or murdering one of us and then only take the very clear cut genuine asylum seekers without pressure to rush the process. Win.