Lance Hayden is a runaway Time Agent portayed by Paul Kay. He first appears in Army of the Ancient Ghosts in Series One, battling with the Doctor to defeat the Kuio onboard the space station in the 27th Century. When the Doctor sent companions Nip and Strider home, he asked Hayden to help stay and fight but seeing that there was no way out, Hayden uses his Vortex Manipulator to teleport away, thus leaving the Doctor to his own fate.
Hayden's next appearance was in the following Christmas Special: Countdown to Christmas where it was revealed that he returned to the space station to rescue the Doctor from the explosion. When his own spaceship gets destroyed when battling the Axons, the Doctor has no choice but to invite Hayden to join him onboard the TARDIS,