Stuart Wheeler - Treasurer, UK Independent Party

When voters feel angry they look for ways to punish their political masters - that's one powerful factor behind the rise of the UK Independence Party, UKIP, a populist anti-EU, anti-immigration movement fuelled by frustration with the status quo. Stephen Sackur speaks to UKIP's treasurer, Stuart Wheeler. Like many UKIP followers he used to support the Conservatives. So, how can he justify the damage he's now doing to David Cameron's party?