But a controversial new history has accused one of the movement's towering figures of encouraging mob attacks on black sailors with "rabble rousing" speeches.
Emanuel – Manny – Shinwell gained national fame for his part as a left-wing trades union official in the worker's revolt of 1919 – which saw a young Winston Churchill order British army tanks into Glasgow's George Square to avert a Scottish revolution.
Seamen's leader Shinwell was thrown in jail for his part in the revolt after he faced down the tanks on 31 January that year – an event known as Bloody Friday. He later returned in triumph as one of the Independent Labour Party's first MPs in the 1922 election – and went on to be a key minister in Clement Attlee's post-war Labour government.
But his hallowed status in Labour history may be tarnished by new revelations unearthed by Stirling University historian Dr Jacqueline Jenkinson.
In her book Black 1919, Jenkinson accuses Shinwell, later Lord Shinwell, of encouraging Glasgow seamen to launch a series of attacks on black sailors.
The historian also reveals how Shinwell's radical seamen's union banned black members.
The claims have provoked an angry reaction from descendants of Shinwell, but other historians said discrimination against black workers – many of whom had fought for Britain in the recently ended world war – had been "glossed over". Jenkinson said: "There has been a reluctance to accept that many of the Red Clydesiders promoted actions that were discriminatory and unfair to the black sailors.
"Manny Shinwell was one of those who campaigned to stop black sailors getting work. His radical seamen's union, the BSU, openly banned black members. It was felt they were keeping Scots out of jobs when they returned from service in the First World War, and lowering wages.
"Shinwell gave quite inflammatory speeches in which he condemned the employment of black sailors in the merchant fleet."
Jenkinson uncovered newspaper accounts from the time that reported Shinwell's role in a Glasgow race riot in 1919 prior to the protest over introducing a maximum 40 hour week to protect jobs.
She said: "He played a celebrated role in the protest in George Square on 31 January 1919. But just a week before, on 23 January, he also played a key role in a very violent attack on 30 African sailors.
"Newspaper reports tell how he spoke to 600 sailors and it was quite a rabble-rousing speech about black and what he called Asiatic, or Chinese, sailors. This led to around 30 black sailors being chased by a baying mob down James Watt Street. They tried to take refuge in a sailors' retreat in Broomielaw, but the mob smashed all the windows and they were turned out on to the street."
Some of the black sailors were attacked and they fought back with guns, shooting one of the mob. One black sailor was singled out and attacked with knives, leaving him with a gaping wound in his back. The police eventually stepped in and arrested the black sailors, with the wounded man taken to court before being allowed hospital treatment.
Jenkinson said: "This was all reported widely in the newspapers of the time, but you rarely hear about this event in the traditional histories of Red Clydeside."
She added: "I certainly do not want to tarnish the memory of the Red Clydesiders, but the story of these black sailors – many of whom had fought for their country during the First World War – needs to be told.
It is ironic that he played a role in this campaign against black sailors when he himself was a victim of anti-semitism."
The claims sparked a furious response from surviving relatives. His nephew, Sir Adrian Shinwell, a prominent lawyer and former chief executive of the Conservative party in Scotland, said: "I find this utterly bizarre. There are lots of family legends about uncle Manny, but this is a completely new one on me.
"As the son of Jewish immigrants from Poland, Manny was well aware of the discrimination that immigrants can face.
"He was not without his flaws, but discrimination against black people was not something he ever encouraged. It is true that you can't defame the dead but I doubt these claims would have been made if Manny were still alive."
Fellow historians have supported Jenkinson's view that discrimination against black sailors on Clydeside has been "glossed over".
Professor Elaine McFarland, a specialist in modern Scottish history at Glasgow Caledonian University, said: "Red Clydeside does have this dark, racist underbelly, and there has been a reluctance to expose it.
"It may be due to the political leanings of some historians, but there has been a sentimental view of those who took part in Red Clydeside.
"It seems to me that this new book is a healthy contribution to the debate."
After the 1919 race riots, which spread to major ports throughout Britain, many black sailors from British colonies in Africa and the Caribbean were forcibly repatriated.
But others settled in Glasgow, continuing to live and work in the city.
Jenkinson said: "Many black people stayed in Glasgow, and many in the city welcomed them. During my research I spoke to one man who remembered the Glasgow race riots of 1919, and he thought it was terrible that they were treated so badly."