Tony Blair was the only leader to allow Immigration ["free-movement"] from Eastern Europe the from moment they joined the EU. Coupled with English being most peoples second language the UK was flooded with people that helped to keep the wages down (by design of course). And who benefited from that? Not the working class.
And Boris was savvy enough to know that if he campaigned on "get Brexit done" he could topple the "red wall" and score a huge victory.
Keir Starmer thinks Corbyn's "socialism" is what cost them the election (2019). No, it was Brexit and possibly Corbyn's "open borders" policy which killed Labour at the polls.
Next election, no-one will be voting FOR Labour, they will be voting AGAINST the Tories.