Families with children will be hardest hit by coalition spending cuts, Ed Miliband has warned.

The Labour leader has stepped up his attack on the deficit reduction plans as he seeks to capitalise on momentum from the Barnsley by-election.

Research commissioned by the party from Landman Economics suggests that on average, couples with children stand to lose around £2,500 worth of public services annually. That is more than £1,000 more than those without children, according to the calculations.

Families where the main breadwinner is aged 25-29 will lose the equivalent of 12 per cent of their income if they have children - and just 4 per cent if not.

Speaking at a conference for Labour councillors in London, Mr Miliband said: "We have always assumed that our children, the next generation, would do better than us.

"Not just the well-off, but the vast majority of people used to expect that their children will do better than them... But there is now a real fear that the British promise will be broken and the next generation will find it harder to get on than the last."

Mr Miliband also insisted that this week's by-election victory showed Labour is "on the move", while the Liberal Democrats were "humiliated".