In the final leaders’ debate on the BBC, the pair clashed over what should happen in the event of a hung parliament, with Mr Miliband telling the SNP leader: “I’m afraid it’s a no. I don’t want to break up the United Kingdom.”
Despite a strong performance by Ms Sturgeon, a Survation snap poll put her second on 31 per cent with Mr Miliband first on 35 per cent and Nigel Farage on 27 per cent.
As five UK opposition leaders sparred in the Methodist Central Hall in Westminster, the focus fell on the battle between Mr Miliband and Ms Sturgeon as
Labour’s 41 seats in Scotland could prove decisive, with a Nationalist surge threatening to wipe them out.
The event was dubbed the “opposition debate” as it was boycotted by PM David Cameron. Liberal Democrat Deputy Prime Minister Nick Clegg tweeted: “For clarity, I was not invited.”
It left the floor to the Labour and SNP leaders, Mr Farage of Ukip, Natalie Bennett of the Greens and Leanne Wood of Plaid Cymru.
Mr Miliband began by mocking the Prime Minister for his absence and “not being willing to defend his record.” He challenged Mr Cameron to an “online head-to-head debate”.
But it was the dynamic between Mr Miliband and Ms Sturgeon which became the focus and sparked to life in the closing stages of the debate, as a member of the audience asked which deals could be struck “in the event of a hung parliament”.
Mr Miliband repeated his line of “fighting for a majority Labour government”, while a confident Ms Sturgeon repeated her offer to “lock David Cameron out of Downing Street”.
But Mr Miliband said he has “fundamental disagreements and profound differences” with the SNP because of Ms Sturgeon’s revelation last week that she might push for a second independence referendum.
The Labour leader said: “I do not want to break up our country, so it’s a no I’m afraid.”
But to applause from a London audience, Ms Sturgeon said: “This election is not about independence, it is about getting rid of the Tories. It is about delivering real change, not pretend change for people right around this country.”
With passion in her voice, she added: “Don’t turn your back on that and let David Cameron back into government.”
But Mr Miliband accused Ms Sturgeon of telling voters to “vote anyone but Labour” and said her approach was “gambling on getting rid of Tory MPs whereas we will get rid of the Tories”.
Ms Sturgeon hit back: “Tell me tonight whether you would rather have David Cameron back in government or work with us.”
Mr Miliband said: “I have a record of fighting Tories all my life”.
He went on to claim the SNP had put the Tories in government in 1979 and Alex Salmond had told English voters to vote Liberal Democrat in 2010 “which ended up with a Tory-led coalition”.
Mr Farage noted: “I can’t see how Ed Miliband could have a government without Nicola Sturgeon’s 35 to 40 MPs.”
The Ukip leader was the only Right-wing leader on the platform and earlier appealed to voters to “take back our country”.
Mr Miliband insisted that there was a “different way” to bring down debt by raising living standards and asking the rich to pay more.
However, Mr Farage went on the attack over the Barnett Formula which gives Scotland a more generous settlement.
He insisted that Ukip is the “only party with a plan to get the debt down” by slashing funding for Scotland, scrapping the international aid budget and leaving the EU.
The contribution brought about the first exchanges as Mr Miliband described Mr Farage’s proposal as “following David Cameron’s extreme plan” which he insisted would “be a disaster for this country”.
But Mr Farage said that he would not offer tax breaks for the rich and accused Labour of “not reading our manifesto”.
Ms Sturgeon accused Mr Miliband “of not being bold enough” and said he was proposing “alternative austerity”, adding: “That is why we need SNP MPs in parliament.”
Ms Sturgeon said: “I don’t say there is not a difference between Ed Miliband and David Cameron – I say there is not a big enough difference between Ed Miliband and David Cameron.”
She added: “I share Ed Miliband’s desire to get rid of the Tories but we don’t need to replace the Tories with Tory lite.”
The attack saw the Labour leader go on the attack over SNP plans for full fiscal autonomy.
He said: “You are not telling people tonight that your plans that will cost £7.6 billion”.
Mr Farage led the arguments in favour of increasing defence spending, saying “we live in a dangerous world”. He demanded that 2010 manning levels in the army are restored.
Ms Sturgeon pointed out that “190 or so out of 200 odd countries in the world do not have nuclear weapons” and said “the Westminster parties have all their priorities are wrong”.
But in an underlining of the differences between the SNP and Labour, Mr Miliband said he would keep Trident.
“As Prime Minister I will not put our defence at risk,” he said.
However, Ms Sturgeon defended Mr Miliband, describing a recent Tory attack on him over defence as “disgraceful”.
“This was a party which sent P45s to soldiers while they were serving,” she said.
Ms Sturgeon also called for “strong” immigration controls.
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