The comparison to Maxine Carr is interesting, and I think there are some parallels. It wasn't quite the same thing because Julie Mugford didn't actually lie, but she did go around with Jeremy for a whole month, and she did withhold evidence from the police - ie, what Jeremy had told her (allegedly). Maxine Carr lied but she didn't know that Huntley had killed the girls.
Could they have prosecuted Julie Mugford for not coming forward earlier though? With Maxine Carr it was more straightforward I suppose.
I asked earlier if Julie Mugford was reviled by the press, and it was the issue of Maxine Carr that made me wonder about that.