Eddie McGrady has been MP for South Down since 1987
The South Down MP Eddie McGrady has said he will not be standing in the upcoming General Election.
The SDLP representative is stepping down from the seat he has represented at Westminster since 1987.
There is speculation that his party leader and former constituency aide Margaret Ritchie will run instead.
The 74-year-old said that after 50 years as a councillor, assembly member and MP he had "recently" decided it was time to step down.
He said that following the election of Mrs Ritchie, there was a "new dynamic" within the party which he still hoped to play some part in.
He added: "I have spent 23 years as an MP representing all the people of South Down and democratic Irish nationalism in the House of Commons.
"I know if SDLP leaders had not been there to challenge the British Government, to act in the interests of the Irish people, nationalists and unionists, and to demand justice and equality for all we would not have peace and no prospect of a better future."
Mr McGrady won the seat in the 1987 General Election when he beat the sitting MP Enoch Powell by less than a thousand votes.
In the last General Election in 2005, he easily fended off a challenge from Sinn Fein candidate Caitriona Ruane, garnering almost twice as many votes.
Mr McGrady said that he would not endorse any individual candidate but that he presumed Mrs Ritchie's name would be among the nominations from which the local party will choose its candidate.
He joked: "They have been very astute in selecting me over the years, so why should they not continue that wisdom?"
Eddie McGrady alongside party leader Margaret Ritchie
Mr McGrady denied that by stepping down he was risking handing the seat to Sinn Fein at the next election.
"The Sinn Fein lead is entirely temporary. Any good political analyst will tell you that," he said.
"In the aftermath of every internal conflict, no matter what country you go to, there is a drift towards the extremes. That drift will come back."
He also denied that his decision to retire had anything to do with the recent expenses scandal, after which the independent auditor Sir Thomas Legg asked him to pay back £3,854.
He did however say that he was "saddened" that MPs were not held in the same esteem as they were when he was first elected to parliament.
One of 11 children, Mr McGrady was born in Market Street in Downpatrick, where his father ran a clothing shop.
He qualified as a chartered accountant and subsequently became a Fellow of the Institute of Chartered Accountants.
He was first elected to Downpatrick Urban Council in 1961.
As well as Westminster, where he has been his party's chief whip since 1988, Mr McGrady was elected to the New Ireland Forum in 1984 and served in the Northern Ireland Assembly between 1998 and 2003.