This study sounds too poorly constructed to form a strong basis for theorizing. For example, what exactly were the relationships of the test subjects to the cultures of the sample speakers? Were working class accents more strongly associated with criminal tendencies by subjects who spoke with the same or other working class accent? Did working class subjects really tend to be more likely to trust people with posh accents? It's all way too vague.

But interestingly, RP accents with sex offenders:

> Participants thought the RP accent was more likely to commit a sexual assault than any of the other offences tested.

> “This finding simultaneously undermines certain traditional stereotypes about both higher status and working-class men,” Alice Paver said. “This may indicate shifting perceptions of the ‘type’ of man who can and does commit sexual offences.

>with accents perceived as ‘working-class’ including those from Liverpool, Newcastle, Bradford and London risk being stereotyped as more likely to have committed a crime

It doesn't mention if they actually do more crimes or not. People perceptions are not automatically inaccurate.