The Tweet from “‘Forgotten Genius” – for many years a PB regular – hits the nail on the head. The Tories won their big GE2019 majority not because of their leader but as a result of the threat of Corbyn becoming PM. As the Tweet rightly points out Johnson was in negative ratings territory
On election day in December 2019 Opinium carried out a survey. One aspect was to find out why previous Labour voters were switching and this chart, which I have used before here, sets it out.