UK prison = our taxmoney is spent to keep him here (it costs us on average £70K a year to keep one prisoner in jail, food, clothing, etc.) and upon release he can still drive arouind on our roads like an arse.
Deportation = might cost us a plane ticket, and who cares if he plows down his own countrymen, will be doing us a favour by cutting down potential immigrants
I know what I'd prefer...