Labour’s Harriet Harman, the longest-serving female MP in the Commons, has announced that she will not be standing for the party at the next election.

Ms Harman, who has represented the south London constituency of Camberwell and Peckham since 1982, revealed the news on Twitter.

She wrote: “After nearly 40 years in Parliament I won’t be standing again at the next election.

“It’s been a great honour to be an MP and to represent Camberwell and Peckham since 1982.

“I will do that with complete commitment and enthusiasm up until the last day! My email to C & P Lab members below.”

Ms Harman’s tweet was accompanied with an image of her letter to Labour members in her constituency.

In it, 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.”

Number of female MPs at ‘critical mass’

Ms Harman also noted the increased representation of female MPs in the Commons, writing: “I 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’.”

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”.

Ms Harman added: “I will leave the House of Commons with my feminism, my belief in Labour and my enthusiasm for politics undimmed.”

Ms Harman was Labour’s deputy leader from 2007 to 2015 and served in a number of ministerial roles under Labour prime ministers Tony Blair and Gordon Brown.

She also stepped in as acting leader when Ed Miliband resigned as party leader in the wake of Labour’s defeat in the 2015 general election.

Labour leader Sir Keir Starmer praised Ms Harman as a “champion for women and social justice” who “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,” he said.

Her announcement comes after two other Labour MPs – Huddersfield’s Barry Sheerman and Barking’s Dame Margaret Hodge – said they would stand down at the next election.