Marion Price

Captain Marion Price was a UNIT officer in the early 21st century. She served as second in command to Colonel Mace and was a senior technical officer. (TV: The Sontaran Stratagem) She was charged with co-ordinating between different countries such as the US, UK, France, Pakistan, India, China and North Korea for a nuclear attack against the Sontaran ship. (TV: The Poison Sky)

Like several UNIT personnel, she saluted the Tenth Doctor upon meeting him which annoyed him. (TV: The Sontaran Stratagem) She also co-ordinated the attack on the ATMOS factory when Colonel Mace led the attack, though it was not clear if she physically participated. Along with Colonel Mace, she watched the atmospheric conversion from the ATMOS factory. As the UNIT soldiers around them cheered, she kissed Mace in a brief loss of self-control before realising what she had done and composed herself. (TV: The Poison Sky)

Behind the scenes
According to Defending the Earth: The UNIT Sourcebook, Captain Price was in command of the aircraft carrier Valiant when it was destroyed by the Daleks during the Planetary Relocation Incident.