On Afghanistan, Brown said "to keep the street safe in Britain, we have to take on al-Qaida wherever it may be." Cameron said Britain would enter into another multilateral military intervention like Afghanistan, but must make sure the British troops are properly equipped and Liberal Democrat leader also criticized that "we cannot allow eight years to elapse until proper equipment is provided to our troops."

(From L to R) British Conservative Party Leader David Cameron, British Prime Minister Gordon Brown, British Liberal Democrat Party Leader Nick Clegg. [Xinhua]

On Climate Change, Brown criticized Clegg over his opposition to nuclear power, saying that "you can't have a balanced energy policy without nuclear." But Clegg said it's just incredibly expensive and it takes too long to build nuclear power stations. While Cameron blamed so many different strategies over the past 13 years for making Britain face an energy emergency.

Domestic issues also topped the agenda during the debate on foreign affairs. The three leaders discussed how to restore faith in the political system, state pension and immigration policy.

On a hung parliament, Cameron said "I don't think a hung parliament would be good for Britain because I do think we need decisive government for the long term." Clegg said he thought there is potential for politicians to work together and he would create a financial council bringing together politicians to all stripes to make decisions on the economy.

The BBC will host the final debate on economy on next Thursdays. After the first TV debate, opinion polls showed that no party will have enough seats to form a majority government although opposition Conservative party are still ahead.