Erisa Magambo

Captain Erisa Magambo was a female officer working with UNIT in the early 21st century.

During Easter 2010 she and UNIT were called out on site after the Number 200 bus had vanished into a wormhole. She, along with Malcolm Taylor, managed to get in contact with the Doctor. When the Doctor warned UNIT that an alien swarm was intent on coming to Earth via the wormhole, she ordered Malcolm to close it despite this meaning that the Doctor and the passengers of the bus would be left trapped on the other side. Malcolm refused so she held Malcolm at gunpoint and insisted he close it due to the danger it posed to Earth.

However the Doctor managed to get the bus back to safety and Malcolm closed the wormhole. She later thanked the Doctor and gave him his TARDIS back after UNIT found it in Buckingham Palace Garden. (DW: Planet of the Dead)

Parallel Worlds
She was part of the operation to remove the Time Beetle on Donna Noble's back. She was in charge of a special division of UNIT, most likely the sole surviving British division in the alternate reality. She, with the help of Rose Tyler, sent Donna back to prevent the events which would result in the Doctor's death and eventual world-wide disasters. (DW: Turn Left)

Quotes

 * "I don't believe it, guns that work!"
 * "Doctor, I salute you whether you like it or not"
 * "Now I've got three dead alien stingrays to clear up, I dont suppose you'd fancy helping with the paperwork?"