Flora Swain was the unmarried sister of Arnold Swain and worked as an assistant at his pet shop. When Arnold abandoned his first wife Margaret he told Flora she had died. Although she thought it unusual that she hadn't been notified of the funeral she didn't question what he told her.
In 1980, when Arnold began an association with Emily Bishop, Flora lived with Arnold in the flat above the shop. She went on living there when Arnold married Emily and moved into 3 Coronation Street, but in December that year Emily discovered that Margaret was in fact still alive and wasn't divorced from Arnold. Before confronting Arnold, Emily sought out Flora, who admitted that she'd thought that Margaret was alive. After getting Arnold to admit that he was already wed when he married her, Emily returned her wedding ring and made him move out of their house.
When Margaret visited Emily in 1982 she revealed that Arnold had left his share of the pet shop to Flora.