Television presenter Jean Johansson has told of her heartbreak over the murder of .
Place in the Sun star Jean revealed the pair knew each other from nursery all the way through to high school.
The Sunday Mail Seven Days columnist said she remembered Margaret, who had learning difficulties, as gentle, kind and caring.
Nine days ago, Eddie Cairney, 77, and Avril Jones, 59, of Inverkip, Renfrewshire, were convicted of murdering Margaret. They will be sentenced on July 17.
Writing in her column, Jean, 37, who, like Margaret, went to Port Glasgow High School, said: “I was relieved the two monsters responsible for her death were found guilty.
"But I was also incredibly sad to accept that Margaret’s body will probably never be found and the people left in charge of ‘caring’ for her are responsible.
“The story is like something from a harrowing Netflix true crime series.
“Reading about it felt surreal, not only because I went to school with Margaret, but also the house where she was kept is in my neighbouring village, so I had a personal interest in what happened to her after she ‘went missing’ 17 years ago.
“It felt awful to hear that police investigating her disappearance had asked if she even existed. She did exist and it’s important to remember she had a life – she’s not just the mysterious girl who suddenly vanished.
“I have memories of her from nursery and Port Glasgow High School. We weren’t in the same classes but I remember her from the playground just being Margaret.
“She needed additional support but, to my memory, she was a happy girl.”
Jean added: “I started a Facebook chat with old school pals and asked for their memories of her – she loved music and liked to giggle, she was quiet but liked being around people and she adored her father.
“The words gentle, caring and friendly kept coming up, making it all the more heartbreaking that those trusted to look after her abused her so badly.”
Margaret was 19 when she was last seen by anyone other than Cairney and Jones.
The pair made the ludicrous claim that Margaret ran off with a traveller, then became a gangmaster who travelled Europe.
Jean added: “Margaret was failed by a lot of people. An old teacher of mine who testified in court stated she was one of the only people who remembered Margaret.
"But that’s not true, we all remember her. As one friend posted, ‘She was a gentle soul, kind and caring and loved a giggle at something funny’.”
It was revealed last week that Cairney and Jones are being pursued for £182,000 by prosecutors. The pair have been served with Proceeds of Crime notices as the Crown Office looks to recover fraudulently claimed benefits.
