Castle also helped make history when she intervened in the Ford sewing machinists' strike of 1968, in which the women of the Dagenham Ford Plant demanded to be paid the same as their male counterparts. She helped resolve the strike, which resulted in a pay rise for Ford's female workers bringing them to 92 per cent of what the men received. Most significantly, as a consequence of this strike, Castle put through the Equal Pay Act 1970. A 2010 British film, "Made in Dagenham", was based on the Ford strike. She was portrayed by Miranda Richardson.