Neville Catchlove

Captain Neville Catchlove was serving with the British Army in South Africa in 1881. (TV: Empress of Mars)

Arrival on Mars
In 1881, Colonel Godsacre - under whom Catchlove was serving - discovered an interplanetary vessel in the South African veldt. On board was an injured Ice Warrior which Godsacre named "Friday". Friday promised the men Martian treasures in exchange for help repairing his ship, enabling them to reach the Red Planet. The ship crashed upon landing, leaving the soldiers stranded on Mars.

While the rest of the men used the Gargantua to mine for gemstones, Catchlove was busy repairing Friday's ship and kept secret how close he actually was to repairing it. Using the Gargantua, they uncovered an Ice Warrior Hive and awoke Empress Iraxxa.

Taking over command
Aware of Godsacre's desertion at Isandlwana and subsequent "bungled" hanging, Catchlove used Godsacre's secret to blackmail him. Catchlove revealed the Colonel's cowardice to his men and had Godsacre, the Twelfth Doctor and Bill Potts arrested and locked in a cell.

The group were freed by Friday. Catchlove having lied about the state of the ship repairs, attempted to make an escape by holding Iraxxa hostage, planning to destroy the lifts with dynamite to keep anyone from following him. However, Godsacre returned and shot the treacherous Captain Catchlove dead, something Godsacre told Iraxxa was an execution. Catchlove's execution and the honor Godsacre displayed caused Iraxxa to agree to peace with the surviving humans. (TV: Empress of Mars)

Personality
When he first introduced himself to the Twelfth Doctor and Bill, Catchlove came off as a charming and gentlemanly man. However, his act quickly faded as events progressed. He showed himself as authoritarian, frequently breaking rank and taking command in Godsacre's place. He had also been blackmailing the latter for an undetermined amount of time.

He was highly fond of himself, to the point of egocentrism. Catchlove at times referred to himself at the third person and proudly proclaimed his own name in grandiose fashion. He was deeply offended when the Doctor referred to humans as "primitives" from an Ice Warrior's perspective and reacted by pointing his gun at Iraxxa.

However, the most prominent trait of his character was his cowardice and ruthlessness. Catchlove purposefully hid the true state of the repairs to the Ice Warrior ship from his men, presumably to keep them working on getting the gems they were seeking instead of trying to flee back to Earth. Once he realised the British Army stood no chance against the Ice Warriors, he was more than willing to save his own life and leave the others to die. He even used Vincey as a human shield when an Ice Warrior had its weapon aimed at him and forced the young soldier to take the blast for him. He also took Iraxxa hostage and started showing slight nervous ticks, possibly indicating he was starting to lose his sanity. Ultimately, he was executed by Godsacre for his crimes, whom he had ironically called a coward before. (TV: Empress of Mars)