Captain Dent is one of the two main antagonists of the Doctor Who story "Colony in Space", the other being the Master.
He was portrayed by the late Morris Perry.
Dent was the captain of an Interplanetary Mining Corporation ship. He was prepared to do anything necessary to acquire mineral deposits and mining rights and was contemptuous of the idea of colonies on other planets, believing priority should be given to the construction of more living units on Earth. He had used a number of unscrupulous methods to ruin colonies on worlds IMC wished to exploit.
Dent and his crew arrived on the planet Uxarius in secret, aiming to drive off the colonists. He used a robot equipped with claws and a holographic projector to make it appear the planet was inhabited by giant lizards. Dent's first officer, Morgan, killed two colonists who stumbled upon the deception but Dent had no problem with the deaths, merely chiding Morgan for allowing himself to be seen. He also had one of his men, Wilfred Norton, infiltrate the colony posing as the survivor of another colony who had been wiped out by the lizards and by the native Primitives. Norton then killed the colony's engineer and sabotaged the power supply.
When the Doctor discovered IMC's presence on the planet, Dent ordered Morgan to have him killed. He then approached the colony leader, Ashe, claiming to have newly arrived on the planet and to have summoned an Adjudicator to decide who should have possession of it. His deception was exposed when the Doctor turned up alive and well. The Doctor and the colonists tried to get evidence of IMC's actions but Dent managed to have it all destroyed and also had Jo and colonist Winton chained to a bomb when they broke into the ship.
The Adjudicator who arrived on the planet was actually the Master in disguise, a fact both IMC and the colonists were unaware of. The Master initially ruled in favour of IMC but changed tack and began to favor the colonists in exchange for information on the Primitives' city. Dent and his men were disarmed and forced to leave in their ship but Dent landed only a short distance away, managing to return and ambush and capture the colonists.
Having realized the Adjudicator was a fake, Dent nevertheless claimed the Adjudicator's ruling made him the legal ruler of the planet. He charged with the colonists with treason and threatened to have them executed if they didn't leave the planet. His engineer, Caldwell, warned him that the colonists' ship was faulty and likely to explode if it took off, but Dent showed no interest in their fate, merely instructing all his men to stay clear of the launch area. When the ship did explode, Dent intended to report that the colonists refused an offer to check it over before launch.
In fact, most of the colonists had survived, with Ashe taking the ship up alone to get IMC off their guard, and managed to surprise and defeat several of Dent's men in a gun battle. Dent's fate is unknown, with the colonists intending to call in a proper Adjudicator to rule on the matter.