A week tomorrow voters in Old Bexley and Sidcup go to the polls in the second Tory by-election defence of this parliament. So far betting has been fairly limited with less than £40k being traded on Smarkets and Betfair put together. In the former the odds on the Tories have now moved to a 94% chance and I just wonder whether, once again, punters have this wrong.

It will be recalled that in June the betting exchange odds on the Tories in Chesham and Amersham had this at a 90%+ chance right up to the point that the count was taking place. The LDs won with a 21% vote margin over the Tories – a result that gave me my biggest betting win.

In the following month the Tories were for a long period odds on favourite in Batley and Spen and again the betting markets proved to be wrong.

It would appear that there is an inbuilt Tory bias amongst punters which at the last two by-elections has proved costly to them..

I have no private information about the Bexley campaign but it does appear that Labour is putting a lot more into it and, of course, the party has edged ahead in the national polls. On a very low turnout in Bexley that could be important and Labour’s current 12/1 on the exchanges looks value.

Mike Smithson