Believe me i know about the Labour party enough to know every time it looks like the left in the Party can take power the Rightwing establishment in the party sabotage it, you can go back to the gang of four who broke away to split the vote and we ended up with the Conservatives again, the right in the party would rather have a Tory Government than a leftwing socialist one, we saw the result in 2019 when they got Bozo the Clown Johnson elected, that was after they were in a panic after Corbyn came close to winning in 2017.
The biggest problem Labour have is that a lot of people just aren't looking at the reality of the situation.
Labour and the Lib Dems got more votes than the Tories in 2010, 2015 and 2017. But the Tories won every one of those.
With Proportional Representation the left would be in power far more. It's also diminish the power of the further left of the Labour Party destroying everything.
People don't want Socialism. They want solutions to the problems, they want a decent NHS, decent education, decent policing etc, but they have two choices and the Tories have a massively unfair advantage.
Really, with PR you'd end up with a center left and maybe Green left and a further left party or groups representing these. This would allow these parties to attract the people who want to vote for these different aspects of left wing politics.
But Labour are exceedingly stubborn thinking that the current system somehow benefits them. It's ridiculous.
Corbyn came in with a different view, but one that ultimately a lot of people are uncomfortable is. Starmer is more palatable, but got lucky in that the Tories were doing so badly. He's proposed nationalizing things, which could lead to another disaster.
British Rail wasn't great. It was cheaper, but they have to find a better way of running it, but will they? I don't have the confidence that a party that has given too much power to the unions can actually do anything other than a system that will benefit the unions.