Britain will later (8pm BST Thursday) watch the only full leaders' debate ahead of a tight general election.
Conservative Prime Minister David Cameron would only agree to take part in one - and only if it also involved a series of minor party leaders.
So 7 leaders will take to the podium tonight to debate ahead of May 7th's vote.
Polls suggest it's the closest race in decades and may well lead to another hung parliament and another coalition government.
Olly Barratt reports from London.
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When David Cameron fired the election campaign starting gun at Downing Street he knew he would only take part in one 'proper' TV debate.
TAKE NATSOUND FROM DEBATE: DAVID CAMERON, UK PRIME MINISTER
"That's not the question… the question is…."
"Well it's the question I'm asking!"
TAKE DEBATE
This wasn't it
The two main party leaders have been quizzed already in front of the same cameras on the same night - but the prime minister wouldn't debate directly with labour leader ed miliband - who was up for it.
NAT SOUND MILIBAND: ED MILIBAND, LEADER, LABOUR PARTY
"AM I TOUGH ENOUGH, HELL YES, I'M TOUGH ENOUGH.."
The polls suggested David Cameron won the first round - the pundits said Ed Miliband did - so perhaps we can call it a draw.
Neither wants to lose the only proper debate which will be about trying to come through unscathed, trying to avoid disaster.
The media will be hoping for a scalp, for a bloody nose…
Something that changes the course of this election campaign.
But with Mr Cameron's Conservatives, Mr Miliband's Labour, the junior coalition partners the Lib Dems, and 7 other parties taking part…it could be chaotic according to Alex Stevenson from politics.co.uk
"It's gonna be a bit of a fight really between all of them I think for oxygen, for attention - the result is that david cameron will be trying to look prime ministerial, along with six other people who think they'd be quite good as prime minister as well."
Simon Hicks from the London School of Economics says he's not surprised David Cameron has been less keen to do a series of debates, than his opposition challenger.
CLIP
If either the Conservatives or Labour are to win this election they need a boost in the polls from this debate.
For now, this campaign remains too close to call - and as unpredictable as any in living memory.
OB LONDON