In my opinion (don't @ me bro): The last credible leader and party we have in this country.
The way I see it, the only remotely "leftist" options we have are Zach "I can make women's breasts bigger through hypnosis" Polanski, Corbyn's not-quite-a-party that can't-quite-decide whether trans people should exist, or the Lib Dems.
As much as people see Ed Davey as a "joke leader" because of his stunts (because the media would only platform Mr Toad otherwise 🐸), I'm increasingly impressed by him. He's on the right side of basically every issue lately, you guys.
And is often the only person who is.
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ETA: He also wrote to Kemi Badenoch and Nigel Farage. His letter alludes to that but doesn't make it super clear.