While I don't disagree 700,000 people a year coming to the UK is unsustainable it's also true that we are building far less social housing per year than we used to. I think we have 2 million less council houses than we did 20 years ago.
I don't know if the table shown in this article is true or not, if it is its shocking how few are being built now.
https://m.belfasttelegraph.co.uk/new.../37332881.html
While you may dislike him, Corbyn would have at least tried to build more social housing, the UK voted against him, twice and it was older people who were more likely to vote against him.