Ed Miliband and Nicola Sturgeon are "at the altar, and preparing to sign the register" on a post-election deal, according to Scottish Conservative leader Ruth Davidson.
Sturgeon made the Labour leader an offer to join forces to help him become Prime Minister during the TV debates.
But David Cameron has warned there would be more borrowing and higher taxes if Miliband goes ahead with the deal.
Ed Miliband insisted his message to Nicola Sturgeon is "thanks but no thanks" following her offer of a vote-by-vote deal to help him become Prime Minister.
"Vote Labour for a Labour government," Miliband told an audience of young people in Lincoln today.
"I think lots and lots of people are jumping way ahead here. I'm working for a majority Labour government," he said.
"I believe we can win a majority Labour government. Let's actually see what happens on May 7."
The Ukip leader said he did not "lose my rag" when he attacked the audience during last night's televised debate for their "left-wing bias."
We watched undecided voters as they watched the debate hoping it might help them make up their minds.
Ed Miliband appeared to turn down Nicola Sturgeon's latest offer as the leaders of five "challenger" parties took part in a heated debate.