Unable to match the Conservatives' billboard blitz, Labour has taken to Mumsnet  in an effort to woo female voters away from David Cameron. The attack ad (see screen grabs, below) targets Tory plans to scale back child tax credits and warns mothers that they'll "get less than they bargained for" if they vote Conservative.
George Osborne promised in his party conference speech  to save £400m by scrapping "tax credits to families with incomes over £50,000". But the Institute for Fiscal Studies last week calculated that such a cut would save only £45m. For Osborne to save £400m, the IFS worked out, he would need to lower the threshold to £31,000, not £50,000.
Labour's decision to target female voters through the campaign is a canny move. It was the defection of women from the Tories that handed power to Labour in 1997, and that secured the party's re-election in 2001 and 2005.
At the last election, 38 per cent of women voted for Labour, compared to 34 per cent of men. Without female voters, Labour's majority in 2005 would have been 23 seats, rather than the 66 it actually won. Women are one of the key groups yet to be won over by Cameron: a recent ComRes poll gave Labour a 4-point lead  among female voters.
As the economy begins to recover, the Tories' plan to curb middle-class welfare could well turn out to be a vote loser. Expect Labour to use this line of attack repeatedly in the election campaign.