Former Labour leader Jeremy Corbyn and current Labour leader, PM Keir StarmerLabour has plummeted to its lowest poll rating since Jeremy Corbyn was in charge of the party.In a major blow to prime minister Keir Starmer, Labour is now at 21% in YouGov’s latest poll on Westminster voting intentions, down one point since last week.The last time support for the party was so low was in October 2019, two months before Labour’s crushing defeat in that year’s general election.Corbyn, who had led the party since 2015, quit soon after and was replaced by Starmer.Relations between the pair broke down after Corbyn was suspended from the party over his response to a probe by the Equality and Human Rights Commission into anti-semitism in Labour.Although he was later re-admitted to the party, Starmer refused to give him the Labour whip back and Corbyn was re-elected to parliament as an independent MP last year.The YouGov poll is further confir