Ross Jenkins

Private Ross Jenkins, code-named Greyhound Forty, was a UNIT soldier during Operation Blue Sky.

Jenkins acted as the Tenth Doctor's escort and driver for the investigation of the Rattigan Academy and he became friendly with the Doctor. They met Luke Rattigan and the Sontaran General Staal. After losing control of an ATMOS-controlled UNIT vehicle, he and the Doctor parted ways so Jenkins could acquire another ATMOS-free vehicle to get to UNIT's temporary headquarters. (TV: The Sontaran Stratagem)

When Sontaran troops invaded the ATMOS factory, Ross was with a small group of UNIT soldiers. He had just enough time to warn the Doctor that UNIT's bullets could not harm them before being killed by Skorr for failing to hide behind a wall. His death was avenged by Colonel Mace. (TV: The Poison Sky)

Personality
Like many of UNIT's men, Ross was a loyal man who obeyed orders from his superiors without question. He respected the Doctor, believing in his final moments that the Doctor was the only one who could stop the Sontarans, though they shared a rather casual relationship while going to and from the Rattigan Academy, the Doctor referring to Ross by his first name and Ross talking to the Doctor like a regular guy. They both found the idea that their vehicles had ATMOS installed despite being suspicious of it stupid, Ross showing a sharp wit and good sense of humour while doing so by saying it "drives me round the bend" just as they were turning right and being proud of the fact that he timed it perfectly.

Ross also said and reacted in ways typical of his age; upon meeting a Sontaran for the first time, Ross described him as a "talking baked potato", and compared the Rattigan Academy to Hitler Youth, though was visibly fazed by his encounter with the former and his near-death experience by their ATMOS. He was generally, however, a likeable guy and faced with death with dignity. The Doctor liked and cared for him, and was very angry that he had died when his death could've been easily avoided, saying his name was Ross when Mace referred to him by his code-name before losing his temper when ordering him to withdraw his men. (TV: The Sontaran Stratagem, The Poison Sky)