Major Cal Kilburne was a UNIT officer. He wanted to debrief Alistair Gordon Lethbridge-Stewart after his mission to Peru.
Later he was trying to stop Sarah Jane Smith from leaving the Black Archive with the Tunguska Scroll. He then went to find Sarah Jane but Gita found him and he told her that he was Sarah Jane's long lost nephew.
When Sarah Jane returned back home it turned out that Kilburne was in fact a member of the Bane Kindred posing as a UNIT officer. He attacked Sarah Jane and her friends but was shot by The Brigadier when he revealed his cane had a hidden gun. (SJA: Enemy of the Bane)