True. The Birmingham 6 had never been convicted of anything prior to their arrests but they were guilty of one of the most heinous crimes of the day, namely being Irish, so that was ok.
Three of the Guildford 4 had previous involvement in petty crime but were also either guilty of the same heinous crime of being Irish or, in the case of Carole Richardson, associating with Irish people.
None of the Maguire 7, including the 13 year old boy, had committed any crime other than being Irish or of Irish descent. The 13 year old boy was convicted age 14 and spent 4 years in an adult high security prison. That's what you get for having an upstanding, law-abiding mother who happened to be Irish.