Kazran Sardick's futuristic wrist watch had been a gift given to him by the Eleventh Doctor. The watch had many functions. It could become a torch and Kazran was also able to link it to the diary that his father Elliot Sardick had given him.
When Kazran and Winston Churchill came face to face with a Dalek, they were forced to power the Dalek's ship. Although neither of them had any experience, the Dalek suggested that the diary had an efficient power source. Kazran reluctantly powered the Dalek's ship using the diary, but was horrified to discover that the Dalek planned to use the ship's weapons systems to kill all life in one-hundred square miles.
As the Dalek prepared to launch its ship, Kazran noticed that his watch was counting down and remembered that the diary was still connected to the watch. Using his watch, Kazran was able to overload the Dalek's ship, causing it to explode. (AUDIO: Living History)