As mentioned up thread, the country Pakistan, I imagine is more reliant on us than we are on them. Revoking visas would be one pressure that could be brought to bear on them, that would pretty much be a one way traffic, I can't imagine too many people from here wanting to make a life there, unless they're ethnically Pakistani going back. Then there is foreign aid.
After all, I remember reading about a criminal in Australia, serial rapist who'd hardly ever lived here, and we had to take him back. Of course no country would want a criminal element back who has long since departed the parent country if they could get round it. From what we read, the Pakistani groomers are far more aligned culturally to the country they emanated from than they are with Britain, a culture which in many instances they deride.