[user104658]

If she's a British citizen then she's our responsibility, is really the be all and end all of the discussion over whether or not she should be brought back into the UK. Countries can't just start saying "not our problem" and exiling. Why would anywhere else want her, either? So if she's dangerous / guilty and needs locked up, so be it, but if she's British then it's Britain that has to provide the cell I'm afraid.