The party leaders will line-up tonight for a high-stakes television debate with the potential to shape the future course of the General Election campaign.
The two-hour encounter - bringing together the leaders of seven political parties - marks the only occasion during the five and a half week campaign when David Cameron and Ed Miliband will debate against each other.
With all the polls pointing to an extremely tight contest, the leaders of the two biggest parties will be anxious to avoid any costly slips while looking for the opportunity to score points at expense of their rival.
The three-way debates in the 2010 election were widely seen to have given a boost to Nick Clegg after he was judged the winner of the first debate - even giving rise to talk of “Cleggmania” - although the effect appeared to fade as polling day approached.
Five years on and no longer the “newcomer”, the Liberal Democrat leader has sought to play down expectations insisting that he does not expect to repeat his triumph this time around.
Instead it may be an opportunity for one of the four smaller party leaders - Nigel Farage of Ukip, Nicola Sturgeon of the SNP, Leanne Wood of Plaid Cymru, and Natalie Bennett of the Greens - to make an impact.
The Conservatives are likely to be particularly wary of Mr Farage seeking to outflank Mr Cameron from the right, while Ms Sturgeon will be looking to underscore the SNP’s position as the biggest party in Scotland with the potential to hold the balance of power at Westminster.
The debate - which is being held at studios in MediaCityUK in Salford - is expected to see the leaders put campaigning on hold for most of the day as they go through their final preparations with aides behind closed doors.
Yesterday they were generally unwilling to say exactly they would be readying themselves for the showdown, although Mr Clegg insisted he would not be losing any sleep.
“I’m not going to have a sleepless night. I have been in politics long enough now to know that you shouldn’t over-think these things or over-rehearse them,” he said.
“I will try and answer the questions as best as I can and make sure that the Liberal Democrat voice is heard loud and clear in the cacophony of other political voices that will be represented on that stage.”
Mr Miliband suggested his approach was just to “keep campaigning” while the Tories suggested that Mr Cameron would point to the gaggle of candidates lined up against him to illustrate the “chaos” that would ensue if the Conservatives were not re-elected.
While Mr Farage had previously insisted that he did not intend to spend too much time getting ready for the debates, Ukip’s campaign chief Patrick O’Flynn admitted he would be preparing “rigorously” in order to make the most of his big opportunity.
“Obviously this will be the only chance he gets to be on the same stage as David Cameron - and that’s David Cameron’s doing, not Nigel Farage’s - so that again means that there will be key arguments to put there,” he said.
ITV said the two-hour live debate, to be screened from 8pm to 10pm, will allow each leader to give an uninterrupted one-minute answer to each question posed by a studio audience of around 200 people.
There will be up to 18 minutes of debate on each question with “four substantial election questions” addressed.
Leaders will not be given advance notice of the questions which have been selected by an “experienced editorial panel”.
After lots were drawn, Ms Bennett will make the first opening statements of the debate while Mr Cameron will speak last.
More business leaders have joined the 103 who wrote to the Telegraph yesterday to praise the “Conservative-led Government” for supporting investment and job creation and lowering the main rate of corporation tax to 20p.
They warned that “a change in course” on May 7 would threaten the recovery.
The 17 extra business leaders include Tory peer and Pinewood Studios boss Lord Grade, Selfridges chief executive Paul Kelly and David Suddens of bootmakers Dr Martens.
Labour last night released its own letter, signed by more than 100 people “from all walks of life”, saying that the country needs a Labour government “to put working people first”.
The party is inviting people to add their names to the letter on its website.