Cilla Maureen Maguire Tutton is the young daughter of Mimi Maguire. Cilla was conceived during Mimi's large string of post divorce flings and her father is a source of much anguish for Mimi, when she realized she had pages of possible candidates. It was later revealed that Mimi's fling with an underage boy named Billy Tutton had resulted in her pregnancy, a fact she knew for some time before being forced to tell her family. Her son's revealed they knew the whole time but were disgusted when Mimi went into detail on how she hadn't had full intercourse with Billy but had masturbated while he stood over her doing the same thing. Cilla was named after the famous singer and presenter Cilla Black, in the word's of Mimi "It's got fuck all to do with being from Liverpool, and everything to do with it being a 'Surprise, Surprise'!" referencing both the surprise pregnancy (which Mimi found out about only when she went into labor) and the Cilla Black TV show of the same title.
Cilla suffered from a life threatening rash in Series 8, as did her brother Shane, brought on by badly dyed carpets. Shane and his wife Kelly were re-decorating the Maguire homestead for Mimi, but in her half crazy sleep deprived state Mimi saw the decorating as a way for the couple to push her out. She also came down very harshly on Kelly over the shoddy carpets and threw the couple out, but after some advice from the apparition of her dead daughter Mandy, Mimi made peace with them.
Mimi's various flings that were possibilities for Cilla's father included a dead man, a blind man who'd had a Vasectomy and a man with a very jealous boyfriend. It was revealed late in Series 8 that Cilla's father was actually Billy Tutton, a young boy who had a fling with Mimi. Billy was 14 at the time and when Mimi found out she was horrified, she managed to scare him away but once he turned 16 he left school and got himself a flat.
Billy snatched Cilla from her pram while Mimi was out shopping one day. After seeing the CCTV footage and realizing Billy had taken Cilla, Mimi was incredibly angry. When Mimi eventually met up with Billy at his flat, she hit him and told him he was still too young to be involved with Cilla. Mimi later became unsure of what to do but when Billy tried to kiss her and told her he loved her, she warned him that he would only ever be Cilla's father, nothing more. She originally told him he would have to win over her son's but when he was unable to achieve this she put her foot down. She explained that she had stood by Jamie when Karen cheated on him and he decided to take her back, she had stood by Shane when he got together with prostitute Kelly and by Micky when he bought a pink limousine. Though she soon discovered her son's had kidnapped Billy, viciously assaulted him and planned to make him leave the estate she decided that Billy would move into the Maguire homestead to be the best father possible.
Cilla was christened in Episode 20 of Series 8. It was at Billy's request that she be christened as Cilla Maureen Tutton Maguire, Maureen after his mother. Mimi allowed this on the condition Billy convert and become a Catholic, which he did. Cilla and Billy were christened at the same time, with Shane and Kelly chosen as Cilla's godparents on account of Mimi not wanting "soft lad" Billy getting full custody if she died.