Sally Harper is a resident of St. Gideon's Home who appeared in Series 3, Episode 5. She is portrayed by Sarah Gordy.
Sally is young woman who was born with Down's Syndrome. When Sally was born, her condition was labeled "Mongolism", an antiquated name that is now considered offensive. Although both Mr. and Mrs. Harper love their daughter, Mr. Harper does not consider Sally "normal" and thinks no one will ever marry her. At age 11, Sally began to wander off, and fearful of their daughter's safety due to her trusting personality and unable to watch her all the time, Mr. and Mrs. Harper sent her to live at St. Gideon's.
When we first see Sally, she and the rest of the young residents at St. Gideon's eagerly await the opening of the ballroom, where a new shipment of goodwill clothes have arrived. The Home plans a dance for the residents, and in the midst of the dance, Jacob can't keep his eyes off Sally as she dances.
A few days later, Mrs. Harper came to visit Sally, but, unusually, Sally wasn't at the steps to meet her. Due to strict regulations, Sally's mother, nor any other visitor, were historically not permitted to visit Sally's room. But, since they are "relaxing" some rules, Mrs. Harper is permitted by the Home's manager, Miss Molyneux, to go on through to see Sally, who is apparently "under the weather".
At seeing her daughter, Mrs. Harper seems to believe that Sally's ailment can be helped by getting up, but Sally complains and clutches her stomach, saying she isn't well. Mrs. Harper asks for her to show her where it hurts, and Sally lifts up her night gown, showing her mother her distended belly. Horrified, Mrs. Harper says it isn't her period, to which Sally replies that she doesn't get them anymore. Mrs. Harper makes her daughter get dressed, and takes her from the Home, despite her and Miss Molyneux's protests.
At once, Mrs. Harper takes Sally to Nonnatus House to be examined by a midwife. As Chummy examines Sally, Trixie and Patsy quietly discuss why Sally's abdomen is distended and why she doesn't get her period anymore. Later, Dr. Turner relates that women with Down Syndrome were not known to be able to get pregnant, and worries that if she were taken to the London Hospital, she would be dehumanized into a curiosity and not an expectant mother. So, he chooses to keep her in Poplar, under his and the midwives' care.
Upon Chummy's examination, she estimates that Sally is 6½ months pregnant. Due to an infection (which caused Sally contractions, thus her pain), Dr. Turner prescribed Sally antibiotics.
The next day, Sally's parents called the police, to find whoever got their daughter pregnant. Naturally, due to Sally not knowing how sex and pregnancy work and how they are related, they fear their daughter was taken advantage of and want the man arrested. Mr. Harper exclaims that he wants to kill the man who did it. Together, Sgt. Noakes and Nurse Miller question Sally in her home, and once alone, Nurse Miller learns that Sally does know that the baby came from getting physical with a man, and also explains that the man was her boyfriend and that it was consensual.
At St. Gideon's, as they pack up Sally's belongings, Nurse Miller and Miss Molyneux discuss Sally's pregnancy and her refusal to name the father. Unknown to them, Jacob Milligan, Sally's boyfriend, and a resident/worker at St. Gideon's, is listening. Jacob makes the long trip to Poplar to see Sally, and when Mrs. Harper answers the door, he asks to see his girlfriend, thereby outting both him and Sally. When Sally sees him, they are both ecstatic, very obviously in love.
Mrs. Harper is very upset at seeing him, not wanting him near her daughter, and still believing he took advantage. Jacob, not deterred, wishes to ask Mr. Harper if he can marry Sally, and "do the decent thing". He then explains that he wanted to see and know that she was looked after by her parents as she was in St. Gideon's, saying if he knew she was safe and loved, he could "go on living". Despite the heartfelt plea, Mrs. Harper still makes Jacob leave.
Once gone, Mrs. Harper expresses her fear that she did not love Sally enough, which drove her to Jacob, to which Chummy replies that she mustn't blame herself.
The nurses are thankful that they have time to "prepare" Sally for the pain of labour, fearing that if she goes into it not knowing what will happen, she will be "traumatised".
Unfortunately, Sally goes into labour not long after, and is in immense pain that she cannot deal with. At the Maternity Home, Chummy tries to give Sally gas and air, but it does not help much. Outside of the room, listening to their daughter scream, Mr and Mrs Harper sit anxiously, near tears. They discuss that the baby will not live, as it will be too small. They seem to be almost comforted by the idea, though sadly so.
Unable to remain outside, Mrs. Harper comes to hold her daughter's hand, listening as Sally cries to her mother that she doesn't want the baby and that she wants to go home.
The baby is stillborn, and as she is catching her breath, Sally asks if it's hurt to which Cynthia replies that the baby was very little. Chummy cries behind the curtain, holding the baby in her arms, and Sally asks if she can go home now. Tom Hereward goes to St. Gideon's to tell Jacob about Sally and the baby.
Mr and Mrs Harper agree to let Sally go back to St. Gideon's on the condition that Jacob leave. To save their facility the humiliation and reputation, the board agrees and Jacob is transferred to St. Mungo's in Scotland, much to his and Miss Molyneux's sadness.
Sally was unaware of his leaving, but as she and her mother walk up the road leading to St. Gideon's entrance, Sally sees Jacob leave in a car. She chases after it, but it keeps going, leaving Sally confused and devastated as her mother watches on.
Sally is given some comfort, however, when she goes back to her old room. There, on her bed, is the sweater she got from the goodwill donations, with a note written by Jacob within it. It reads "Love, From Jacob". Sally holds both the sweater and note close, her eyes tearing up.
In series 6 it is revealed that St. Gideon's has closed down. It is unknown where Sally ended up.