Ewan McColl is a pseudonym: he was Jimmy Miller until deserting from the Army during WW2. I think McGrath's description is fair enough, but for some reason McColl did describe himself as Scottish.

"Sweet Thames" was the one written for a modern radio version of Romeo & Juliet. "Dirty old town" was written to cover a scene change in one of the numerous socio-political plays he wrote for Theatre of Action and Theatre Workshop in the 30s,40s and 50s.

He was one of the major influences in agitprop theatre which sowed seeds of dissent in working-class communities across Europe in the 30s - just never got to be trendy like Brecht. It was only after teaming up with Peg Seeger around 1955 that he became primarily a singer songwriter. Before that, most of his songs were written merely as props for his stage work. Before, during and after WW2, he and Joan Littlewood (who was his wife for a while) were frequently hassled by the law, as were their productions, and both were blacklisted by the BBC (they were of course both Communists).

He was a true internationalist, with his outlook being strongly influenced by the Russian revolution, and steeped in causes like independence for India, the republican side in the Spanish Civil War, etc,just as much as the working-class struggle in Britain.

"Manchester Rambler" is presumably the one he called "I'm a rambler." That and songs like "Shoals of Herring" and "Freeborn Man" must put him up with the all-time greats.