The leaders of Britain's three main political parties have held a second televised debate, trading heated opinions on foreign policy.

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The leaders of the two main parties were again frustrated by Nick Clegg, the challenger from the Liberal Democrats, whose rise in popularity promises to make this election one of the UK's closest.

Clegg enjoyed an unexpected boost following the first debate, propelling his party from third place into first in some polls.

Analysts said that another strong performance from the Liberal Democrat leader would virtually guarantee that the election produces a hung parliament with no clear winner.

Gordon Brown, the Labour prime minister, and David Cameron, the leader of the Conservative party launched stinging attacks on Clegg, with the prime minister at one point telling him to "get real" over his plans to reduce spending on nuclear weapons.

Al Jazeera's Alan Fisher reports.

Source: Al Jazeera