Joshua Naismith
Joshua Naismith was a 21st century Earth billionaire. He lived in Great Britain and was known to employ a private army. He was responsible for Neon, a phone advertised on the side of the 200. (DW: Planet of the Dead). He also wrote the book Fighting the Future.
After the fall of the Torchwood Institute, he aquired the Immortality Gate, a device of Vinvocci design. He captured the Master and forced him to repair it. He wanted to use it to give his daughter Abigail immortality. Instead, the Master used it to turn everyone in the world into a copy of himself, including Naismith. (DW: The End of Time)
Behind the scenes
'Naismith' is another instannce of Russell T Davies reusing names; his earlier Century Falls features a Dr. Josiah Naismith.