Next London Mayor - market mayhem

There are signficnat discrpancise in this market. Following Johnson's slection (which was a foregone conclusion!), the best prices availible at 8.15 p.m. today (Thursday) are:

Livingstone (Skybet) 4/5
Johnson (Bluesq) 2/1
Paddick (Coral) 25/1

I find this market very hard to call. With an over-round book of 93%, there has to be value, I'm just not sure where! (Comments welcome). Of course, I could arb but with the stakes I can get on, I woudn't win a great amount. However, anyone who has an unrestriced account (*unlike me :) ) could have substantial three figure amounts on the 2 front runners making a tidy profit.