Born in a working-class family, MacDonald left school at 16. She became politically active in the Independent Labour Party and then became secretary the Anti-Parliamentary Communist Federation in Glasgow. She eventually worked for the United Socialist Movement (USM). From then on she was associated with Guy Aldred in the Workers Open Forum and United Socialist Movement.
She lived in a menage-a-trois with other anarchists in Gibson Street in Glasgow, Guy Aldred and John Caldwell. Her mother was quite angry with her, especially as Aldred was an atheist. At 94, Caldwell recalled:

We were separate individuals who sometimes had it off a wee bit. When Ethel and I were in public, we were separate people . . . sex had nothing to do with other people. But she believed I could have as many friends as I liked and she could, too. [1]

In October 1936, the USM sent her to Barcelona to report back for the organisation. She travelled to Barcelona with Jane Patrick to assist the anarchists in the Spanish Civil War. She worked as a radio announcer for the Confederacion Nacional del Trabajo (CNT). As the English-speaker, she was listened to in Europe and America. She also wrote for Scottish newspapers. According to Caldwell,

her broadcasts went down very well. Some of the American newspapers said how pleasant her Scottish voice was.

She was behind some of the first reports on the 1937 May Riots, when leftists turned against each other, resulting in death squads of Stalinists assassinating prominent anarchists and 400 people being killed in street fights in Barcelona.
In the crackdown following these events, anarchists in the independent Marxist party, POUM, were rounded up in June 1937.
She often endangered her life, visiting anarchists in prison, smuggling in letters and food and helping some escape in borrowed clothes and on foreign ships.
She was imprisoned by Stalin’s secret police, but while the world fretted about her disappearance, she organised hunger strikes among the anarchist prisoners and smuggled out letters. After questions about her absence in the Houses of Parliament and an American newspaper campaign, supporters formed the Ethel MacDonald Defence Committee. Even in California, people were concerned for her safety when she was arrested and the Scottish papers called her a Scarlet Pimpernel.
International pressure was applied and she was deported to France. She returned to Glasgow in November 1937.
She told the crowds of her experience:

I went to Spain full of hopes and dreams. It promised the utopia realised. I return full of sadness, dulled by the tragedy I have seen.

Ethel MacDonald continued to campaign throughout her life against Stalinist attacks on the POUM and the anarchists. She worked with Aldred and other Glasgow anarchists on producing propaganda, notably The Word.
She died in 1960 of multiple sclerosis.
Alison Murphy, producer of the new film, came across her story while working on the BAFTA-nominated documentary Against The Tide – George Orwell, another International Brigades volunteer. “The beauty of this story is not only that it is forgotten, but that it shows what an extra ordinary path her life was to take: from humble beginnings in Lanarkshire to Spain, where she would place herself at the heart of a fierce struggle,” she said.
References
– Boztas, Senay (Arts Correspondent), "Revealed: amazing life of Scottish Pimpernel. Seventy years after the the efforts of ’forgotten’ activist Ethel MacDonald are recognised", The Sunday Herald (Feb 13, 2005)
– Caldwell, John Taylor. With fate conspire: memoirs of a Glasgow seafarer and anarchist. ISBN 0952316714
– Hodgart, Rhona M. Ethel MacDonald: Glasgow Woman Anarchist. Kate Sharpley Library, 1997. 23 p., 21cm. pamphlet. ISBN 1873605285
– A film, "Ethel MacDonald – An Anarchist’s Story" is in preparation by Alison Murphy. See: [Lily, "Ethel MacDonald’s life made into movie" Infoshop Saturday, February 12 2005