Cameron and Clegg
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David Cameron and Nick Clegg head to head on voting changes

The prime Minister and deputy prime minister are to set out the opposing views on possible changes to the voting system for Westminster elections which will be put to voters in a referendum on 5 May.

People will be asked if they want to replace the first-past-the-post system with the Alternative Vote, the ranking of candidates in order of preference.

Carole Walker sets out the argument.

Go to next video: Gloves come off for AV votes campaign