A mum of three has told the BBC she has had to go into debt to pay for childcare.
Jane Carmichael who has three children said affording summer childcare was "impossible".
Research shows London parents pay a weekly average of £177.13 per child for summer holiday childcare, 25% more than the figure in the east of England.
A government spokesperson said it was "rolling out the single-biggest investment in childcare in England".
The spokesperson added that the government's childcare programme was "set to save a working parent using 30 hours of childcare up to an average of £6,500 per year".
But Ms Carmichael, who is from Uxbridge in west London and was a founding member of the Women's Equality Party, believes that more investment is needed.
She told the BBC: "It's affected my career many times over. When I had two children in childcare it was just about affordable, that was just about affordable. As soon as a I had a third, I know that that was my choice, it tipped us over the edge.
"I was going into debt to have a career."
She said it would cost her £60 a day over the summer to pay for each of her children to attend a childcare facility.
