Harriet Harman, Labour’s former deputy leader, has said she will step down at the next election after around 40 years in parliament. The mother of the house – the title given to the female MP with the longest continuous service – said she felt she could move on from the Commons with renewed faith in her party’s future. Harman, 71, the MP for Camberwell and Peckham, was first elected in 1982. In an email to constituents, she said: “I feel I can leave the House of Commons now confident that Labour is gaining strength under the leadership of Keir Starmer and the new team he has appointed. “It has been an overwhelming honour to be member of parliament representing and working for the people of Camberwell and Peckham for nearly 40 years.” Harman served as acting Labour leader in 2015 and deputy leader from 2007 to 2015. Under Tony Blair, she was secretary of state for social security and the first minister for women, and has held numerous other cabinet and shadow cabinet positions. She said she had fought 10 general elections, served under seven prime ministers and eight Labour leaders. She said she had “entered the Commons as one of only 11 Labour women MPs in a parliament that was 97% men. Now there are 104 Labour women and across all parties women MPs are a ‘critical mass’.” But she said there “remains much more to be done till women genuinely share political power with men on equal terms and until women in this country are equal. I will leave the House of Commons with my feminism, my belief in Labour and my enthusiasm for politics undimmed.” In her email, Harman said she remained extremely proud of the achievements of the Labour government, citing the national minimum wage, Sure Start centres, the Equality Act and investment in education and the NHS. The Labour leader, Keir Starmer, said Harman had “paved the way for future generations”. “Harriet, your commitment to Labour and Camberwell and Peckham for almost 40 years is phenomenal,” he said. “A champion for women and social justice – you’ve paved the way for future generations. “It’s been a privilege to work with you, I look forward to continuing to do so for a while yet.” Ed Miliband, who led the party with Harman as his deputy between 2010 and 2015, described her as “a feminist, fighter, conviction politician”. “Harriet taught me so much as my first political boss and was a brilliant deputy,” he said. “She has achieved so much and will be sorely missed from the House of Commons.” The shadow culture secretary, Lucy Powell, said Harman had been a “trailblazer for women”. “She’s incredibly effective, very loyal, fierce, formidable and very kind. She taught me so much,” she said. Two other long-serving Labour MPs, Barry Sheerman and Dame Margaret Hodge, have also announced their plans to stand down at the next general election. The party is understood to have asked MPs to inform them if they intend to step down, so it can begin to make preparations for new candidates.