Jo Grant's uncle

 was the uncle of Jo Grant. His position at the United Nations (AUDIO: Storm of the Horofax) enabled him to arrange for Jo to get a job at UNIT. (TV: Terror of the Autons)

Canning had arranged for Jo's fitness to for UNIT to be tested by having her encounter various obstacles when Jo was on her way to meet her uncle for lunch. On her way to meet her uncle, Jo found herself being pursued by a car, chased through the woods by men dressed up to look like insect-like humanoids, encountered Sergeant Benton dressed up in a velvet suit and wig (standing in for the Doctor), and successfully overpowered several of her captors as they attempted to take her back to the hotel where she was meant to meet her uncle. When she finally does meet her uncle, he explains the situation to her and informs her that she passed her test and was now officially a member of UNIT. (AUDIO: Taken For Granted)

Jo once visited him while he was convalescing at Kenstone Hall, a recovery home for injured spies. While at the facility, she discovered that its patients were undergoing inexplicable healing and that its director had been replaced by. (PROSE: The Touch of the Nurazh)

Jo visited her uncle in hospital numerous times over the years. He eventually passed away and his house was torn down. Years later, convinced Jo he was her uncle as part of his plan to obtain a vial he’d conditioned Jo to steal from UNIT. Jo eventually realised the truth, however was left unable to remember her true uncle as she could only remember the Master in his place. (AUDIO: A Quiet Night In)