An MP who quit the Labour Party in a protest over Jeremy Corbyn's leadership will not stand in the next election.
Ann Coffey, who has represented Stockport since 1992, made the announcement on Twitter.
The 73-year-old, who became a founder member of Change UK, said she made the choice after "a lot of consideration".
She was one of seven Labour MPs who resigned in February amid concerns about Mr Corbyn's stance on Brexit and alleged anti-semitism in his party.
Ms Coffey said it had been a "great privilege" to have represented Stockport first as a councillor in 1984 and then as an MP since 1992.
"I have enjoyed being an MP and campaigning on the issues that matter but after a lot of consideration I have decided not to stand for election again," she said.
Ms Coffey thanked constituents for their "support and kindness" and said she wanted to "wish you and your families the very best for the future".
The former social worker campaigned vociferously victims of child sexual exploitation and is chairman of the All Party Parliamentary Group for Runaway and Missing Children and Adults.
In October 2014, Ms Coffey published an influential report commissioned following the 2012 Rochdale child sexual abuse scandal.
She served as Tony Blair's parliamentary private secretary in his first years as prime minister, and was later worked under chancellor Alistair Darling.
Prior to Labour's 1997 victory she had served as shadow health spokesperson and in the whips office.