John Smith, who died of a massive heart attack 20 years ago this Monday, was robbed of the chance to find out if he could lead Labour back into Downing Street after the party had spent more than a decade in opposition.
Ed Miliband today leads tributes to Mr Smith by praising his "gravitas, decency and integrity".
The Labour leader recalled the shock felt by so many when Mr Smith died suddenly at his London flat at the age of just 55.
He said: "I remember very well, like so many, the day John died. I saw an evening newspaper with the terrible, sad news. For me, it led to an immediate sense of immense shock, disbelief at the loss.
"They were emotions felt by so many in the Labour movement and across Scotland."
Mr Miliband, who began his political career in the early 1990s as an aide to Harriet Harman, then Shadow Chief Secretary to the Treasury, explained: "The times I met John Smith, like everyone, I saw the gravitas, decency and integrity that so many people saw.
"It was the loss of those characteristics and attributes that made the whole of Britain mourn his passing."
The Labour leader stressed how, 20 years on, the world now felt very different.
"Some of the things he fought for were implemented by a Labour government, including the minimum wage and a Scottish Parliament, that he dreamed of all his political lifetime."
Mr Miliband noted, as Scotland decides its future, how Mr Smith had argued all his life for devolution within the United Kingdom and against independence.
He added: "For him, politics was about equality, social justice, decency, never walking by on the other side. These are the values that John Smith believed in. These are the values we continue to fight for."
Mr Smith's friendships went beyond party political boundaries and included Sir Menzies Campbell, the former Liberal Democrat leader, who recalled how a curious coincidence had brought him, Mr Smith, Derry Irvine, Donald Dewar and John Mackay together at Glasgow University in the 1960s.
Sir Ming said: "By various and sometimes unexpected routes all of us finished up at Westminster but it was a racing certainty that John Smith would do so.
"A lawyer by trade, he was a natural politician, even as a student and, of his contemporaries, the one most likely to succeed."
The Fife MP explained that it was Mr Smith's skills as a fearless advocate and a brilliant pleader in front of a jury that made him such a formidable parliamentarian.
"All of this suggests a serious and dedicated individual but he was more than that. As Donald Dewar famously said, John Smith could start a party in an empty room and often did so.
"He was a brilliant raconteur and, with Elizabeth his wife, a generous and compelling host. In the early hours it did not take much to persuade him to begin singing with a startlingly wide repertoire of Gaelic, student and bawdy songs."
Sir Ming recounted how "more than once with a mixture of disappointment and frustration he asked me why the - expletive deleted - I was not a supporter of the Labour Party like my parents. My answer, that it was because I was a liberal, was wholly inadequate and summarily dismissed."
The ex-party leader, who will step down as an MP at the next General Election, remembered how Mr Smith joined a group of left-leaning lawyers, who dubbed themselves the Radical Mountaineers, and took to hill-walking "with the same enthusiasm as he did everything else".
Sir Ming added: "In truth, John Smith was a good companion, who was devoted to his friends and lit up all of their lives."
Another friend and colleague, Lord Foulkes, noted how many people had speculated what "might have happened if John had not been taken so cruelly from us at the early age of 55. Certainly, he would have won the General Election in 1997 with a Cabinet of enormous talents including Tony Blair, Gordon Brown and Robin Cook".
The former Scotland Office Minister recalled the description of Mr Smith by his widow: "a Labour loyalist by instinct and a pragmatist by inclination".
"That," added Lord Foulkes, "is why John is my hero."