What would they have to do if they were to decide that the deal is more important than the UK? - merge everywhere else but the UK (presumably that would mean s

What would they have to do if they were to decide that the deal is more important than the UK? - merge everywhere else but the UK (presumably that would mean spinning off/closing one of Microsoft or Activision UK branch). I guess that wouldn't be enough? - both companies have to pull off of the UK?