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The Corby by-election controversy

14 November 2012 Last updated at 14:17 GMT

The Conservatives' campaign manager for tomorrow's Corby by-election has apologised after being filmed apparently admitting that he encouraged a rival candidate.

In the covert footage Chris Heaton-Harris suggested his friend James Delingpole, a Daily Telegraph writer, had put his name forward as part of a "strategy" against onshore wind farms.

Speaking on The World at One, the BBC's political correspondent Ross Hawkins explained what has been going on in the campaign.