Mark Whitaker was the husband of Rebecca Whitaker. He was a senior partner at the solicitors of Pollard, Boyce & Whitaker.
In 2011, Mark encountered a Weeping Angel, which sent him back in time to June 1994. In the past, he used the alias Harold Jones to avoid suspicion, and followed instructions from a letter he thought to be written by his future self, allowing him to both influence events in his past and convince the Eleventh Doctor to leave him in the past so that the timeline could play out as it should. However, the letter was later revealed to be psychic paper sent to him by a group of Weeping Angels, with the instructions simply appearing in the handwriting of whoever was holding it. The Angels wanted Mark to save his wife, who had died in a car accident on 10 April 2003. Since this would create a paradox, as without his wife's death he would have no reason to want to travel back in time and would thus negate their entire relationship after all the 'aid' provided by his future self, the Angels would then be able to feed on the resulting paradox. After the Doctor, Amy and Rory were able to trap the Angels, Mark eventually decided against saving his wife, and then returned to the present in the Doctor's TARDIS. (PROSE: Touched by an Angel)