Broadcasters have written to Britain's main political parties proposing a series of televised debates before the general election.

The BBC, Sky News television, and ITV have written to the leaders of the Labour, Conservative and Liberal Democrat parties with a joint proposal for three live televised debates before the election, which must be called by the middle of next year.

Sky News has been campaigning for U.S.-style debates between Prime Minister Gordon Brown and opposition challengers David Cameron and Nick Clegg.

The idea has been endorsed by Cameron and Clegg but Brown has been slightly more circumspect.

Brown's Downing Street office did not immediately return a call Friday seeking comment on the proposal.