The betting exchange, Smarkets, has just put up this market in anticipation perhaps of what might happen once MPs have all digested the Gray report.
For me what makes betting on a Johnson loss good value are the market rules which state:
This market relates to the result of any no confidence vote in Boris Johnson held by the Conservative parliamentary party. This market will be void if no vote is held in 2022.
My reading is that the 54 CON MP requirement for a confidence vote to take place will only be met provided that there’s a belief that Johnson would not survive it. So if the view is that there isn’t the support to oust him then those CON MPs who are hostile to Johnson will hold their fire.
If a confidence vote does not take place by the end of the year then the market will be void and you will get your money back.