LABOUR leader Ed Miliband warned of a "quiet crisis" among the middle classes yesterday as he said that earning £44,000-a-year no longer guaranteed financial security and acknowledged that immigration had depressed wages.

He also called for tax breaks for firms that pay staff a "living wage" or offer training towards better-paid jobs.

Support for a living wage has already come from a number of Scottish organisations including Glasgow City Council and Scottish Enterprise.

Launching a new review into living standards, Mr Miliband said increasing financial pressures meant many families would struggle even if the economy improves.

He also threatened to enter into a spat with Peter Mandelson, describing the former Business Secretary as a "writer not a quitter these days" when questioned on comments in the peer's updated memoirs.

New research released yesterday suggests that middle-class families will be around £4000 a year worse off this year, as a result of spending cuts and a fragile economic recovery.

Mr Miliband said: "For many decades rising prosperity benefited the bulk of the working people.

"But that assumption is breaking down ... The result is a quiet crisis that is unfolding day by day in kitchens and living rooms in every town, village and city up and down this country."

Mr Miliband also said immigration from Eastern Europe had depressed pay while Labour was in power.And he warned that families who earn £44,000 a year, the threshold for the higher rate of tax, could still find themselves squeezed.

While a new poll last night suggested Labour is winning the battle for the "squeezed middle".

Overall Labour is leading the Tories by 4%, the survey shows. But among the lower middle classes that figure rises to five points (38% to 33%) and among skilled manual workers to 11 points (44% to 33%).

However, the Tories enjoy a large advantage among the top AB social group, leading by 41% to 33%.

Overall, the ComRes poll for the Independent puts Labour on 39%, down three points from a similar poll two weeks ago, and the Tories on 35%, down one.