Joining the Independent Labour Party at an early age, Barbara Betts became immersed in a culture of socialist Sunday schools, Labour churches, propaganda meetings, a radical local newspaper, the 'Bradford Pioneer,' and the progressive and influential Bradford Trades Council.
She went to Oxford in 1929, one of her lecturers being the famous theorist G.D.H. Cole. At this time the Left organisations at Oxford were buzzing with ideas and people, and it was this aspect of university that Castle enjoyed, rather than the more prosaic academic studies.
Disappointed by obtaining a Third, Betts returned to where her parents were now living in Hyde. She became propaganda secretary of her local party, an unusually high profile position, especially for a woman at that time. Eventually Barbara Betts found work demonstrating products to shopkeepers, this work was to take her to London before she was sacked, gaining "a useful insight into the hierarchical rigidities of private enterprise." By this stage involved with pamphleteer William Mellor and the Socialist League, in 1937 she became a district councillor for St Pancras Borough Council.
Faced with expulsion when the Labour leadership refuted any Popular Front, by implication disaffiliating the Socialist League from the Party, Betts agreed to dissolve the League. The 'political timidity' of the official Labour Party seemed out of keeping with a fearful Europe facing aggression.
A freelance reporter in London during the Blitz, Barbara Betts
spoke at the 1943 party conference with some impact. She
also married Daily Mirror journalist Ted Castle in 1943. With
women's position in Britain beginning to change, constituency
Labour Parties began to come under some pressure to select women
candidates. In 1944 she was selected to fight the Blackburn seat
at the next General Election.