Sir Gerald Kaufman, the Labour MP for Manchester Gorton and Father of The House of Commons, has died aged 86, sparking a by-election in his constituency.
The MP's family said he died on Sunday evening after suffering from a long-term illness.
Labour Party leader Jeremy Corbyn paid tribute to the MP as an "iconic and irascible figure", saying: "He loved life and politics. I will deeply miss him, both for his political commitment and constant friendship."
Sir Gerald was first elected as Manchester Ardwick MP in 1970 before becoming Manchester Gorton MP after constituency boundary changes in 1983 until his death.
His family announced his death "with great sadness", saying: "Sir Gerald had been suffering from a long-term illness for several months but in that time, remained firmly committed to and focused on the activities and wellbeing of his beloved constituency, which he had served since first elected in 1970.
"Sir Gerald dedicated his life to serving those who he believed would benefit most from a Labour government and Labour values in action.
"He believed that policy and principle without power were simply not enough to deliver the better life that he fought for on behalf of his constituents for almost 50 years."
Commons Speaker John Bercow paid tribute saying: "I was very saddened to learn of the death of Sir Gerald Kaufman, the Father of the House and Manchester Gorton's outstanding representative.
"Gerald was a passionate campaigner for social justice, here in Britain and around the world.
"His passing will be mourned by his relatives, friends, constituents and colleagues."
Labour MP for Streatham Chuka Umunna paid tribute tweeting "very sad to hear of Sir Gerald's death" and described him as "a true Labour man and one of the most eloquent parliamentarians".
The constituency is seen as one of Labour's safest seats and so the by-election resulting from his death is unlikely to cause any headaches for Mr Corbyn.
Mr Corbyn received calls to step down as leader after losing Copeland to the Tories last week in a by-election.
Conservative grandee and former chancellor Ken Clarke is now the new Father of the House, the title given to the MP with the longest continuous service who is not a minister.
Mr Clarke was also elected in June 1970 but Sir Gerald held the title as he was sworn in first.
Sir Gerald's last spoken contribution in the Commons chamber was in a debate paying tribute to the Queen on her 90th birthday on April 21 last year, according to Hansard, the official report of proceedings in Parliament. He spoke of wanting to reach a similar milestone.
"Turning 90 is a marvellous signpost in life, as I hope to experience myself before long," Sir Gerald said.
"Not long ago, one of my sisters turned 90 and we had a huge family celebration.
"Today, the national family is celebrating, and that very much includes those in this House."