Johnson (Children of Earth: Day One)

Dedicated MI5 enforcer for the Government who has been assigned the job of dealing with Torchwood at the start of the 456 crisis. Ruthless and efficient, she has little time for social niceties and is determined to see her job done efficiently and successfully. After killing Captain Jack Harkness a number of times, she used a laser cutter to implant a powerful bomb in his abdomen. After she had used Dr Rupesh Patanjali to lure Harkness to  this fate, Johnson ruthlessly shot him in the back.