Since MacKenzie's gamble, the odds have shortened to 7/2. Bookies William Hill, which took the wager, gave him odds of 4/1, so that if Iain Duncan Smith leads his party to victory, the radio boss will win £40,000.
MacKenzie's is the biggest bet on the Conservative Party returning to government since the 1997 general election. Labour is still firm favourite to triumph in 2005 or 2006, with odds of 1/6. The Liberal Democrats are 50/1.
Perhaps MacKenzie is confident that his one-off broadcast last month on Channel 4, 'Kelvin Saves the Tories', in which he put forward his own manifesto for the party, could help turn around the "natural party of government"'s fortunes.
In the show, which was watched by a paltry 600,000 viewers, MacKenzie suggested abolishing tax for anyone earning under £30,000, bringing back the death penalty, "pulling up the drawbridge" on asylum seekers and sending them to a new holding centre -- France.
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