PC Sally Armstrong arrives at Sun Hill after completing her probationary period and being transferred from Harringay. She previously had a desk job at a telemarketing firm but realised it was not for her. She joined the police force because she wanted a physically demanding job that would also give her a challenge in life and a good salary. She soon realised that being a police officer was her ideal job.
Sally arrives at Sun Hill on the same day as probationer P.C. Billy Rowan. Whilst investigating a break-in with Billy, Sgt., Nikki Wright and P.C. Emma Keane, she and Emma worry that they cannot contact Billy or Nikki, so they call for backup. After backup arrives it is discovered that Billy's throat had been slashed. Sally is traumatised but assures Inspector Gina Gold that she will be back at work the next day. Sally becomes good friends with P.C. Keane. Sadly for Sally, Emma dies in an explosion, but as a hero because she saves the lives of many others. This left Sally devastated.
Sgt. Stone tried to save Emma by giving her CPR, but she was already dead. Sgt. Stone felt he was responsible because while he was preoccupied with something else, he allowed Emma to walk off on her own into harm's way.
At the end of the episode Demolition Girl, Sally goes out clubbing with her colleague P.C. Benjamin Gayle, where she gets rather drunk and kisses him, when Ben says that he doesn't want to do anything because she's too drunk she gets annoyed and heads to the bar for more drinks.
At the bar she chats to a man whom she ends up kissing outside the club, she starts to have flash backs of the days events and pushes him of her and heads to her car. Sally starts the car and drives off ending up with her having a car accident. It carries on into the next episode 'Over The Limit' where Ben is helping an unharmed but shaken Sally out of her car. The passenger from the other car is in a much worse condition, but luckily she does not die. Ben gives the paramedics a false name and Sally goes to hospital to be checked out.
Ben calls Sgt. Callum Stone and tells him what happened. Both Ben and Callum go to the hospital and get Sally out before any police can see her and begin to cover up what she has done, by disposing her car keys down a drain, placing her bag on a street with her cash and cards removed so that it would seem that her car was stolen. They also convince a witness, the man she had been outside with, to say that he saw her leaving with Ben. TD.C. Will Fletcher also helps cover up Sally's mess. With no CCTV footage or any other evidence Sally had been driving she is in the clear.
But she starts to feel really guilty about whats happened and decides that she is going to hand herself in, but Callum convinces her otherwise when he explains that it wouldn't just be the end of her career. He also said that she will have to prove to him that Ben, Will and himself did not all pervert the course of justice for a waste of space and that she will have to earn his forgiveness. It later comes to light that the accident had not been caused by Sally but a man who was driving an illegal minicab and had fallen asleep at the wheel. Sally left Sun Hill without explanation in December 2009.
- 2007 - Joined Sun Hill as a Police Constable
- 2008 - Helped a Barton street officer hide his stash of drugs
- 2008 - Crashed car after drinking which Sgt Callum Stone covered up
- 2009 - Resigned from Sun Hill
- PC Ben Gayle - both showed interest in each other.
- Fling with Sargent Smith
- Fling with Detective Constable Will Fletcher