The Opposition at Westminster is now on 41%, up three points, while the Tories have slipped four to 29%. The Liberal Democrats have also lost ground, down two points to 13%, and UKIP, the anti-European Union party, has risen three points to 9%.
One worrying detail for David Cameron will be the gender breakdown, with Ed Miliband's party enjoying a seven-point lead over the Tories among men but a 26-point lead among women.
Meanwhile, on the economy, 29% of people blamed the economic slowdown on Labour's "debts - racked up to finance unsustainable spending"; the same level as last May when the same question was asked.
However, the number of people blaming the Coalition for the downturn has risen over the same period from 17% to 23%.
Labour's 12-point advantage comes after two similar polls at the weekend gave leads of nine and 10 points.
The result comes after Mr Cameron's speech on a possible EU referendum and proposals to shake-up childcare provision.
Among the assorted other parties, the SNP is at 2% (down one point on the month), while Plaid Cymru holds steady on 1%. The Greens too have shown no change at 2%, while the BNP stands at 2%, up one point.