Nicola Sturgeon has said people across the UK will not forgive Ed Miliband if he turns down the chance to lock the Tories out of Downing Street.
During Thursday night’s television debate, the Labour leader rejected calls from the First Minister to work with the SNP to prevent David Cameron from returning to power.
Ms Sturgeon was back on the campaign trail in her hometown of Irvine in Ayrshire on Friday, where she was congratulated on her performance in the showdown, which also featured Ukip leader Nigel Farage, and her Plaid Cymru and Green allies, Leanne Wood and Natalie Bennett.
“Ed Miliband knows as well as I know that if there is an anti-Tory majority in the House of Commons after the election then the only way David Cameron gets back into Downing Street is if Ed Miliband stands back and lets him back into Downing Street,” she said.
“If Ed Miliband and Labour do that, they will not be forgiven, certainly in Scotland and I suspect in large parts of the UK as well.”
She added: “It was very clear last night that on its own, Labour is not going to be bold enough to offer a real alternative to the Tories.
“That’s why SNP MPs are so important, so we can hold Labour to account, keep Labour honest and make Labour bolder than it will be on its own.”
Ms Sturgeon’s comments came as Scottish Labour prepared to launch its manifesto in Glasgow.
The party is trailing the SNP in the polls, and Mr Miliband has already ruled out governing in a formal coalition with the nationalists after the May 7 vote.
The SNP has ruled out any deal with the Conservatives but said they would be prepared to support Labour on a vote-by-vote basis.
David Cameron has pressed Mr Miliband to rule out co-operating with the SNP on an informal basis.
Mr Cameron said in a Twitter message to voters: “Ed Miliband won’t rule out a vote-by-vote deal with the SNP so he can be PM. It would mean more borrowing and more taxes and you would pay.”