Colonel Martin Janus is a villain in the Thunderbirds Are Go! episode Chain Of Command.

A member of the Global Defence Force, he uses a recent failure by International Rescue at a bridge rescue as an opportunity to demand increased regulation of the organisation, to the extent that they will be required to inform the GDF of occasions when they intend to take action rather than their current free pass to intervene when the situation requires their aid.

Despite the apparent legitimacy of his decisions after their mistake, the Tracys are still suspicious of Janus's actions, a suspicion that is reinforced when Lady Penelope Creighton-Ward and Parker meet with him and Parker asks subtle questions about his alleged career, with Janus making key mistakes in describing his regiment's past actions. When Janus attempts to use International Rescue's defiance of his orders during an attempt to rescue two people trapped in a high tower as a chance to seize Thunderbird 2, the Tracys refuse to cooperate just as Lady Penelope finds evidence that Janus is a fake. Combined with Brains' discover that the bridge the team failed to save was rigged to collapse, Janus is arrested and taken into custody.

While in prison, Janus is confronted by the Hood, who reveals that he was behind Janus's position but his minion played his hand too early to be any true use to him.