In the early hours of June 16, 1995, Claire Harrison received a phone call she would never forget.

Islington Gazette: Jane Harrison was last seen on June 15 1995Jane Harrison was last seen on June 15 1995 (Image: Archant)

“My sister Maxine rang to say that [my older sister] Jane had gone missing. I was immediately concerned because it was so out of character,” Claire told the Gazette.

“I rang the local police, the local hospitals and A&E – and when I knew she wasn’t anywhere to be found, I stood in my bedroom and cried my eyes out. I said to my partner: ‘My sister’s gone and we’re never going to see her again.’”

It was only 18 years later, in 2013, that Jane’s boyfriend Kevin Doherty, Buckhurst Hill, was finally convicted of her manslaughter and jailed for 12 years. The conviction was based on circumstantial evidence – to this day, the body of Jane, who lived in Poet’s Road, Highbury, has never been found.

But the sisters are not ready to give up hope of a break-through. Last week, they appealed through BBC’s Crimewatch programme for any information that might help.

“I appeal to anyone who knows anything to put themselves into our situation,” said Claire, 47. “If they’ve got children, think how they would feel if their loved one just vanished. Because you can’t just get on with your life as though it hadn’t happened – it’s impossible.”

By locating Jane’s body, Claire believes the family would finally find some closure. Among those affected are Jane’s two sons, now aged 22 and 35, as well as two grandchildren who will never know their grandmother.

Speaking for the family, Claire added: “I don’t talk about it as much now, because people have heard it all before, but to us it just seems like yesterday that she went missing.

“Doherty is suffering for a few years in jail, but our suffering will go on for life.” The loss, she says, has been especially hard for Jane’s eldest child, from a previous relationship, who was just 15 when his mother disappeared.

“He’s a broken man – it’s affected him so much. He’s gone through so many things in his life where he’s been angry, bitter and frustrated.”

Jane’s youngest child, whom she had with Doherty, has no memory of his mother at all. “We spoke about her every day at home and never kept anything from him, but he can’t remember the bond he had with her,” said Claire.

Claire hopes that by finding her sister’s body, the children, who were brought up by Jane’s mother who died before Doherty’s conviction, will finally be able to come to terms with their mother’s death.

“They deserve to have somewhere to grieve for their mother,” she said.

The family hopes that Doherty may have let slip some information about Jane – whether to a cell-mate or to a friend or family member on the outside over the years.

“Really, there’s only one person who could definitely help, but we hope that he has made the mistake of telling someone,” Claire said. “It’s a big secret to keep for 20 years, and it has eaten away at me – so I can only wonder at how he must feel.”

Call the Crimewatch on 0500 600 600, police on 020 8345 3985 or Crimestoppers on 0800 555 111.