Zack Polanski speaks to candidates and campaigners during a campaigning visit to Brixton. Photo by Justin Tallis / AFP via Getty Images It was a warm Thursday evening in late April, and I was on the Number 35 bus in south London, travelling from Herne Hill to Brixton. I was accompanying Michael Chessum, a former speechwriter for Jeremy Corbyn turned Green Party candidate for the Brixton Acre Lane ward in Lambeth in the upcoming local elections. We were on our way to join some of his fellow Green candidates for an evening on the doorstep. As we left Herne Hill, Chessum was grinning at his phone. The campaigners we were on our way to meet had texted to say that a group of miserable-looking Labour activists had also gathered in the same area as a gaggle of enthusiastic Greens. Chessum’s baby daughter was strapped to his front in a black papoose. Several of his colleagues described her as his “secret weapon”; she has accompanied him on most of his door-knocking rounds.…