I mean, it was supposedly from an ipsos poll, but he was maybe tied with them? I'm from the US looking in, but the general sentiment I always have heard was that he started out claiming to fix the issues the Tories caused, but backpedaled hard and ignored the wants of basically everyone in the voting base. This obviously backfired so badly that it messed up a lot of down ballot support for labour in the last elections, enough that the party basically had to force him out (behind the scenes obviously, labour didn't wanna seem "weak") and get Andy Burnham in (probably the most popular labour politician currently) to stop the bleeding.