Jean Corston, the Labour MP for Bristol East, is to stand down at the next General Election, it has emerged.
Ms Corston has strong links with civil liberties groups
Mrs Corston, who was elected to parliament in 1992, told party members in the city at a meeting on Friday.
The MP hurt her ankles in 2003 in a fall at the House of Commons and says she has never really fully recovered.
In 2001, Mrs Corston became the first woman to be elected chair of the Parliamentary Labour Party - the 'shop steward' of the back benches.
Mrs Corston has strong links with feminist and civil liberties groups.
"I had been confident that I would make a full recovery from injuries to my ankles.. That has not happened," Ms Corston said.
"I have come to accept that I will not have the stamina to fight a vigorous election campaign and represent Bristol East effectively in the House of Commons.. because the work is physically demanding."
Prime Minister Tony Blair said: "Jean is a hugely respected figure and will be greatly missed from the House of Commons.
"I am sure I speak on behalf of the whole Labour party when I wish her and Peter all the very best for the future."