(There is a spoiler for "Northanger Abbey" at the end of this post)

I know that shortly after JA's period (e.g. in Dicken's time) it was possible for a woman to sue a man to whom she was engaged if he then failed to follow through by marrying her. I expect (but don't know) that this applies to the Regency period also.

We see in many of JA's works that parents held a near veto right over their children's marriages - it was rare and imprudent to marry against your parents' wishes.

How do these interact? If a man were to propose (without having cleared it with his parents first) and be accepted, and then his parents refused permission, could he use this as a reason to break the engagement without risk of legal action?

The immediate stimulus for this question is in Northanger Abbey - Isabella evidently believes herself engaged to Captain Tilney (otherwise she would not have broken her engagement to James Moreland) yet he (Cpt Tilney) 'escapes.' I was wondering whether he could have used refusal of parental permission to defang potential legal action? (A problem with this is that he didn't ask for permission prior to breaking the supposed engagement.)

In this particular case, there is another possibility for avoiding legal action - Captain Tilney could threaten to expose in court her duplicity in courting him while engaged to James. The damage to her reputation might outweigh any monetary damages she might get.