Why do you believe Labour are a far left, Marxist party? Is that your own opinion after reading their policies or your opinion from what the media have told you? It might be interesting to note that in most parts of Europe Labour would currently be considered a centre-left party, yet the right wing press in the UK have been on a scare mission as they're petrified of having a party come into power that might actually clamp down on their tax avoidance. That's why they backed Brexit.
If your opinion is based on reading Labour's policies first-hand, then fair enough. If it's based on what the media say, then grow some balls and do your own research.