DAVID Cameron and George Osborne were yesterday accused of launching a massive attack on women after research on the Coalition's changes to tax, pay and benefits shows they will lose almost £2 billion as a result.

And in another broadside from Labour, the Prime Minister and his Chancellor were accused of "picking the pockets of children" because more number-crunching reveals almost 375,000 in Scotland will miss out on £41 million under changes to working tax credits.

Research from the House of Commons Library, obtained by the Opposition, has found 4.6 million women and 2.6 million men will be affected by the UK Government's two-year 1% cap on pay rises in the public sector. The cap will cost women £687m a year by 2014/15 compared to £388m for men.

Some 89% of those affected by a change to child tax credit will be women, who will lose £908m a year against £112m for men.

This means almost three-quarters of the extra £2.37bn raised by the Chancellor from tax credit cuts and public sector pay caps will come from women.

"This is the biggest attack on women in a generation," said Ed Miliband as he answered questions from a female audience at a meeting in London.

Yvette Cooper, Labour's equalities spokeswoman, added: "The Government's plans are deeply unfair on women. They clearly don't understand the pressures many women are facing at the moment – especially women with children who will lose most of all."

Opinion polls have shown support for Mr Cameron among female voters has been ebbing away. The PM is said to have been stung by criticism he is regarded as more sexist than other party leaders.

A leaked memo from No 10 said: "There are a range of policies we have pursued as a Government which are seen as having hit women, or their interests, disproportionately."

It has subsequently emerged Mr Cameron is to appoint a female aide to advise about the impact every Coalition policy has on women.

The PM accepted it was difficult to cap public sector pay on top of a freeze as it was to uprate benefits at the top end of inflation, but he insisted the Government was trying to be "fair, compassionate and helping those who are least able to help themselves".

Asked on ITV1's Good Morning why the Coalition was penalising the bottom third of the population, who would be hardest hit by the new changes, Mr Cameron replied: "If you look at the overall numbers, the top 10% pay 10 times as much as the bottom 10%. That's right and that's fair."

In a separate development, John Robertson, the Labour MP for Glasgow North West, said analysis of the Autumn Statement showed the Government's decision not to go ahead with the £110 increase in the child element of working tax credits would take away £41m from 373,200 children in Scotland alone.

"This Government are going to pick the pockets of children and the budgets of hard-pressed families before the pockets of bankers," said Mr Robertson.

Last night, a Treasury spokeswoman said: "These figures are a completely distorted view of what the Government is doing to support women. They totally ignore the £650m the Government committed this week to doubling free childcare for two-year-olds, which will help women back into work, along with an increase in the child tax credit of up to £135 per child."

She added: "There is absolutely nothing fair about running huge budget deficits and burdening future generations with the debts we cannot afford to pay. If the deficit is not tackled now, the impact on women and families will be worse in the long term with less money to deliver the public services that women rely on."

Meanwhile, the PM signalled the way child poverty is measured could be changed.

The Treasury acknowledged that as a result of the changes in the Autumn Statement child poverty will rise, using the current formula, by about 100,000 in 2012/13. Yet, Mr Cameron insisted the current formula – a child is in poverty if he or she is living in a household with below 60% of average income after housing costs – was problematic.