Sergeant Alec Peters was an old-fashioned copper with a touch of Dixon of Dock Green about him. He was one of the original three sergeants at Sun Hill along with Bob Cryer and Tom Penny. He was a friend of Bob's, though in some ways Alec saw Bob as a rival. The two men were both up for the desk job of Duty Sergeant. Peters turned it down; Cryer accepted it. By contrast to Tom Penny, Peters was a jovial sort, not averse to sharing a laugh and a joke with the Relief. Alec was genial and friendly, though not above a little petty jealousy. But like Penny's, his health and career went downhill after he was the victim of violence. Peters was stabbed in the stomach by a kid on drugs while out on a housing-estate raid. He recovered eventually but was never mentally or physically the same, needing to resort to pills and the occasional strong drink on duty. The incident had such a profound effect on him that he was moved 'upstairs' to a desk job where he could quietly see out the remaining years to his retirement.
Alec's last regular appearance was in the 1992 episode Trials & Tribulations. He wasn't seen again until Ted Roach's funeral in September 2004.