Liberal Democrat Lynne Featherstone failed to hang on to Hornsey and Wood Green, losing to her Labour rival Catherine West by 11,000 votes.
Her defeat leaves the Lib Dems with no women in Parliament.
Ms Featherstone, who was the most senior Jewish minister in the coalition, had held the north London seat since 2005, winning a majority of 6,000 five years ago.
Mrs West thanked her celebrity backers including actor Steve Coogan for helping her unseat Mrs Featherstone after a tensely fought campaign.
She pledged to fight for the Living Wage for her constituents and to protect the NHS from cuts.
She said the big swing to Labour "reflects the discomfort and dissatisfaction in our area with the previous Coalition Government and the Liberal Democrats' part in that.
"There is disappointment with Tory values - the breaking up of the NHS, the cruel and unfair bedroom tax and the real lack of hope for young people, who are particularly affected by and struggling with London’s lack of affordable housing.
"The voters in my area decided the result on fairness. Despite the economic recovery which is talked about, in fact most people in London have not felt the benefits financially, with their bills rising.
"The London Living Wage and my pledge to fight for that for everyone has been popular on the doorstep.
"I came into politics to make people’s lives fairer. That is what I will campaign for now I have been elected."
Ms Featherstone gave an emotional leaving speech.
She said: "We had a mountain to climb and we could not do it. I would like to thank the people of Hornsey and Wood Green for allowing me to represent them. It has been a privilege."
She fought the election using her credentials as a local having gone to school in the constituency and said that the unravelling of the Liberal Democrat vote nationally did not mean the coalition had been a bad thing.
She said: "We have suffered but I still think coalitions are a positive thing."
