John Maclean (1879-1923) was born in Glasgow, Scotland into a family of Highland origin. Maclean became a school teacher and then attended the University of Glasgow, graduating with a Master of Arts degree (Maclean always used MA after his name when being published thereafter). Maclean is viewed as one of the leading figures of the Red Clydeside era.
Maclean became convinced that the living standards of the working-classes could only be improved by the adoption of Marxist thinking and he joined the Social Democratic Federation (SDF), and remained in the organisation as it formed the British Socialist Party. By the time of World War I his socialism was of a revolutionary nature, although he worked with others on the left whose socialism wasn't, such as his friend James Maxton. He heavily opposed the war as he felt it was a war of imperialism which divided workers from one another.
His politics made him well known to the authorities of the day, and in 1915 he was sacked from his teaching post. As a consequence he became a full-time Marxist lecturer and organiser, educating other Glaswegian workers in Marxist theory. He would later found the Scottish Labour College.
During World War I he was active in anti-war circles and was imprisoned for his efforts in 1916, being only released after left-wing demonstrations following the Russian Revolution in February, 1917.
It was around this time that Maclean become more nationalist in thought and he eventually formed the Scottish Workers Republican Party which combined Communism with a belief in Scottish independence. This action alienated him from UK Marxist leaders. H. M. Hyndman, one of the leaders of the SDF was particularly critical, just as he had been of James Connolly when he established his Irish Republican Socialist Party in 1896.
Maclean was made Soviet Consul in Scotland by Lenin in reward for his revolutionary socialist efforts.
When Maclean died, his health broken by years of imprisonment, several thousand people lined the streets of Glasgow to see his funeral procession pass, such was the extent of his reputation by the time of his death.
He left a legacy that has subsequently been claimed by both the Scottish Nationalist and Labour movements, making him fairly unique in this respect amongst Scotland's historical figures. The modern Scottish Socialist Party strongly lay claim to Maclean's political legacy, particularly the Scottish Republican Socialist Movement (a faction within the SSP).