The family then moved to Manchester, and Munro found work with the Midland Railway Company.
[1] Munro became interested in socialism, and was an early member of the Independent Labour Party, and later also the Openshaw Socialist Society.
[1] Munro worked at Crossley Motors during World War I, becoming a shop steward, taking a leading role in the city's shop stewards movement, and a 1917 strike at the factory.
That year, he resigned from the CPGB, unhappy that it had criticised leaders of the Trades Union Congress during the UK general strike.
In 1936, he was elected as secretary of the trades council, aligning himself with the Labour Party and becoming increasingly opposed to the CPGB.