Tributes have been paid to former Labour politician Giles Radice amid reports he has died aged 85.
Labour party leader Sir Keir Starmer praised the former MP and peer as a "wise and kind man" and "unrivalled social democratic thinker".
In a message posted on Twitter, Sir Keir said: "Giles Radice represented Labour in Parliament for five decades.
"He was an unrivalled social democratic thinker and his work was a vital part of Labour's path to 1997.
"He was also a wise and kind man whom I had the pleasure of spending time with. My thoughts are with his family."
Former prime minister Sir Tony Blair said Lord Radice was "one of the unsung heroes of Labour's long march back to power" after its defeat in 1979, and "represented the best of intellectual talent".
"He was hugely thoughtful, clear-sighted and with a keen understanding of Labour history," he said in a statement.
"He used all of those gifts to map out a serious and sensible path to power for Labour during the long period of opposition before the 1997 election.
"I personally found him immensely helpful, supportive and insightful. I used to listen to him and be persuaded by him.
"He was also good-natured and kind-hearted, loved by those who knew him well. My deepest condolences to Lisanne and the family."
Shadow health secretary Wes Streeting also described Lord Radice as an "outstanding parliamentarian, a Fabian, and a moderniser to his fingertips".
"He understood the futility of opposition and how Labour wins. I feel privileged to have known him and benefited from his wisdom," he tweeted.
Lord Radice was elected as an MP eight times over the course of a Commons career spanning nearly three decades, representing the now-abolished Chester-le-Street constituency, and later North Durham, between 1973 and 2001.
He was appointed to the House of Lords in 2001 and served until his retirement in 2022.
During his time in Parliament he sat on Labour's frontbench as shadow education secretary in the 1980s, and went on to chair the Treasury Committee from 1997 to 2001.
He was also an author of political books and pamphlets, with shadow chief secretary to the Treasury Pat McFadden describing his writing as "beautiful and hugely informative".
Labour MP Kevan Jones, who now represents the North Durham constituency, tweeted: "Sad to hear the news about the passing of my predecessor, The Rt Hon the Lord Giles Radice.
"My thoughts are with Giles' wife Lisanne and the family at this difficult time."
