In terms of the vote share, Ladbrokes is offering 20/1 (4.7%) on Johnson getting less than 40% of the vote, 5/1 (16.7%) on 40%-50%, 3/1 (25%) on 50%-60%, 7/4 (36.3%) on him getting between 60%-70%, 3/1 (25%) on 70%-80% and 12/1 (7.7%) on his getting more than 80% of the vote. Paddy Power takes a similar view on the vote share Johnson is likely to win. It is offering 12/1 (7.7%) on less than 40%, 7/2 (22.2%) on 40%-49%, 3/1 (25%) on 50%-59%, 9/4 (30.8%) on 60%-69%, 10/3 (23.31%) on 70%-79%, 9/1 (10%) on 80%-89% and 20/1 (4.7%) on 90%+.
Early polls suggest Johnson has the support of around 60% of Conservative councillors, but I think this will come down as his many weaknesses and characters flaws are exposed. I think that it’s more likely than not that he’ll get less than 60% of the vote. I’m therefore going to recommend that you bet on Johnson getting either 40%-50% or 50%-60% with Ladbrokes at 5/1 and 3/1 respectively. This works out at combined odds of 50%. To split a £10 betting unit properly, put £3.33 on 40%-50% and the rest on 50%-60% (the bet is void if either candidate withdraws).