Her television credits included playing Cathy in a 1967 BBC production of Wuthering Heights, Doctor in the House, The Avengers, Coronation Street, Penmarric, As Time Goes By and You Rang, M'Lord? (in the recurring role of Lady Agatha Shawcross).

She was a niece of Actress Margaret Johnston. She moved in with actor Leslie Phillips in 1977, at which time she was pregnant by another actor. She brought up her son with Phillips, and, following Phillips' former wife's death in 1981, she married him in 1982.

Scoular suffered from depression and anorexia nervosa. She attempted suicide in 1992 by slashing her wrists with a knife. It was revealed in March 2009 that she was suffering from colorectal cancer; she was eventually declared cancer-free, but in the months preceding her death she had feared its return. Weeks before her death, she was arrested for drunk-driving. She died on 11 April 2011 after ingesting acid drain cleaner and pouring it on her body, causing lethal burns to her digestive tract and skin. She was survived by Phillips and her son Daniel. An inquest at Westminster Coroner's Court on 20 July 2011 established that Scoular had been an alcoholic and suffered from depression and anxiety about debts; she was on medication for bipolar disorder at the time of her death. The coroner recorded that Scoular had "killed herself while the balance of her mind was disturbed", and stated that her death was not suicide.