Ed Miliband has sent a strong signal that he does not want Labour to enter a coalition with the Scottish National Party (SNP) following the general election.
But despite being pressed repeatedly, the Labour leader did not rule out a deal with Nicola Sturgeon's party if the May 7 poll results in a hung Parliament.
A Labour/SNP coalition has seemed much more likely in the wake of polls that suggest the pro-independence party will take a large numbers of seats from Labour north of the border, while Labour and Conservatives run neck-and-neck nationally.
Such a deal could see Scottish independence return as a big issue after last year's referendum.
Former SNP leader Alex Salmond has said he believed the Yes campaign would win a second referendum and he expected to see independence within his lifetime.
Asked whether he will seek a coalition with the SNP if the election result is not conclusive, Mr Miliband told BBC1's Andrew Marr Show: "I am not about deals and coalitions.
"I am about one objective. I am going to put foward a manifesto before the British people and say: 'This is a plan to put working people first, not a plan for the privileged few like this Government has. It is a plan for working people to raise people's living standards'.
"I want a majority Labour government to put that into practice."
He added: "I've got an old-fashioned view on this. A majority government is what this country needs - a majority Labour government.
"This is our election to win and the right thing to do is to spend these four months talking about these huge issues the country faces, talking about how we are going to improve people's wages so hard work is rewarded again, give opportunity to our young people and restore the NHS.
A Labour deal with the SNP is a very real possibility
"It's a very clear statement of principle from me that my focus in the coming months is going to be on winning that election, winning a majority government."
Recent polls have suggested that a resurgent SNP could double its 20% tally from the 2010 election in May, costing Labour 20 seats or more.
A new YouGov poll for the Sunday Times put Labour and the Conservatives equal on 32% in nationwide voting intentions, with Ukip up five points compared to a similar survey on Friday on 18%, Liberal Democrats on 7% and Greens on 6%.