Reid came to prominence in the early 1970s, when he led the Upper Clyde Shipbuilders work-in to try to stop Edward Heath's Conservative government from closing down the shipyards on the River Clyde. The government had decided that the shipyards should operate without state subsidy, which would have resulted in at least six thousand job losses. An engineer by trade and shop steward of the Amalgamated Union of Engineering Workers, Reid, along with his colleagues Jimmy Airlie, Sammy Gilmore and Sammy Barr, decided that the best way to show the viability of keeping the yards open was by staging a work-in rather than by going on strike. This meant that the workers would continue to complete what orders the shipyard had until the government changed policy.