The gloves came off in the second televised debate of the General Election campaign, as the leaders of the three big parties clashed over issues ranging from nuclear weapons to Europe, immigration and expenses.

In contrast to last week's well-mannered exchanges, Gordon Brown, David Cameron and Nick Clegg made direct attacks on one another in the 90-minute debate in Bristol.

Mr Brown accused Mr Cameron of being "a risk to the economy" and Mr Clegg "a risk to our security".

The Conservative leader challenged the Prime Minister to disown Labour campaign leaflets which he said were peddling "lies" over Tory policy on benefits for the elderly.

And Liberal Democrat leader Nick Clegg accused the Tories of allying themselves with "nutters and anti-Semites" in the European Parliament.

After a widely-praised performance in last Thursday's debate which catapulted his party up the polls by as much as 12 points, all eyes were on Mr Clegg to see whether he could repeat his surprise victory in instant surveys of viewers. Both Mr Cameron and Mr Brown were criticised for giving the Lib Dem leader an easy ride in the first debate, and were quick to pick up on what they regard as flaws in his programme.

As Mr Clegg repeated his attack on MPs from "the old parties" who had flipped their second homes to maximise their income from expenses, Mr Cameron stepped in to warn him not to place himself "on a pedestal".

And the Prime Minister addressed him directly over his opposition to a like-for-like replacement of Britain's Trident nuclear deterrent, telling him: "I have to deal with these issues every day and I say to you, Nick, get real."

Mr Brown accused the other two leaders of "squabbling" like children as they clashed over their proposals for referendums on the European Union.

Mr Cameron dismissed the Lib Dem call for a vote on whether Britain should quit the EU as "a con", while Mr Clegg accused the Tories of wanting to leave the UK standing on the sidelines.