Britain's political classes united in grief over the untimely death of Labour leader John Smith on this day in 1994. He was 55.

The Scotsman died after suffering two serious heart attacks, the second in an ambulance on the way to St Bartholomew's Hospital in London where he was pronounced dead at 9.15am.

The shockwaves caused by the sudden loss of the leader of a resurgent opposition reverberate to this day. It is no exaggeration to suggest that his passing changed the course of British history.

With John Major’s administration reeling in the aftermath of Black Wednesday, the keys to 10 Downing Street were well within Smith's grasp.

John Smith with deputy leader Margaret Beckett and shadow home secretary Tony Blair after Blair's speech at the 1992 Labour Party Conference in Blackpool.

Instead, his death triggered a contest for the Labour leadership. Three years later, under Tony Blair (with Smith and Margaret Beckett, above), Labour won a massive majority at the general election. 

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Members from both sides of the House remember Smith as a man of intelligence and integrity, and many in the Labour movement describe him as the best prime minister Britain never had.