David Cameron has mocked Labour for using a driver from the Unite union to drive its campaign bus.
The wheels came off Labour's plan to persuade more women to vote amid a mini-row over the party's decision to use a pink bus as its tour vehicle.
Harriet Harman, who is leading the bid to get more women to vote Labour, also revealed to The Huffington Post that the driver of the bus was provided by the Unite union - giving the prime minister an easy hit.
Speaking during prime minister's questions today, Cameron said the use of the colour pink was "patronising" to women. And gleefully took aim at the driver. "We now know it's not going not be driven by anyone on the front bench, surprise, surprise it's going to be driven by Unite," he said.
Ed Miliband had used his questions to go on the attack over Tory links to HSBC, the bank which has accused of aiding tax evasion. The Labour leader said Cameron was "rotten" and was a "dodgy prime minister surrounded by dodgy donors".
The Labour 'woman-to-woman' campaign hopes to address at least some of the 9.1 million women who failed to vote in the 2010 election.
Harman had told HuffPost: "Unite [the union] has provided us with a driver. She added: "We’ve had lots of doctrinal discussions, such as: should we be alright with a male driver?" Asked if the colour pink was a bit of stereotype, Harman added: "Well it doesn’t have big eyelashes on the front."
Labour's deputy leader told ITV News this morning: "I think the one thing that women will be discussing with us will not be probably the colour of the bus, they'll probably be discussing whether they get the same pay as men in their workplace, the same opportunities, whether they are tearing their hair out looking for childcare, whether or not, if they're looking after older relatives, they can combine that with work."
Nick Clegg also mocked the vehicle as "the Barbie bus", telling the Western Morning News: "It's just a tiny bit condescending because it's bright and pink therefore women relate to it more.
"It's a bit like saying that political parties should drive around in macho red sports cars and blokes across the country will suddenly listen to them."