Will Ulez be the undoing of Sadiq Khan?

In his politics column for The Spectator this week James Heale profiles the three candidates that the Tories have shortlisted for London mayor. With the seventh London mayoral election coming up, can the Tories capitalise on Sadiq Khan's declining popularity recently, and offer some answers in the ongoing Ulez debate? Cindy Yu speaks to James Heale and Dave Hill the former Guardian London commentator who now runs the website On London.  Produced by Cindy Yu and Oscar Edmondson.