I hadn't realised you were only 13 years old.
In fact the worst party leader in your lifetime, in your terms of success in gaining votes and getting Labour power is currently Tony Blair, and, before you try to correct me, note my use of "currently" and look at the facts.
It was Blair who introduced devolution, making it possible for the SNP to rise to dominance in Scottish politics. By common consent, once the SNP through nationalism took the majority of seats in Scotland, it destroyed any realistic chance of Labour holding power in the UK parliament, given England's fundamental small "c" conservatism and Labour having always been heavily dependent on the Scottish vote since its Scottish founder to have any chance. Worse still, the same devolution led to the rise in Welsh nationalism enabling Plaid Cymru to also take UK parliamentary seats. Ergo, Blair with that one policy did more to wreck a party's electoral chances than any other party leader in modern history.
And before I finish witn Blair, let me remind you of his Tory nature and its betrayal of Labour's socialist values, most clearly shown in his introduction of of the failed PPI policy and it's very costly consequences, a true Tory policy if ever there was one, mortgaging the future of the young for the sake of short term profit. And then of course was his promotion of the Iraq war and it's devastating consequences. That didn't only wreck Iraq and subsequently Afghanistan, it led with inevitability to the mythical Arab Spring and the current devastation of Libya and Syria.
For Labour, for the UK, for the World, Tony Blair is now by a huge margin the worst UK party leader in your lifetime.
Not that he lacks some competition. We had Theresa May, a disastrous Home Secretary who went on to lose her party many seats and its majority in the Commons in an unnecessary general election, and now we have Boris Johnson, having done immense harm to London when Mayor, then becoming an appallingy bad Foreign Secretary and now a bumbling wreck of a Prime Minister, damaging everything he touches.
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