How Mary's disappearance became a haunting mystery

Her family thought she was going to a New Year's Eve party but Mary Flanagan was never seen again. Harriette Boucher looks inside the UK's longest-running missing person case

- Harriette Boucher

Mary Flanagan was just 16 when she vanished. A bubbly, lively teenager, recently engaged and adored by her three younger siblings, she had her whole life ahead of her when she disappeared without a trace.

She is now regarded as the subject of the longest-running known missing person case in Britain.

Thanks to an incredible outpouring of public support, The Independent has raised £165,000 to launch SafeCall – a free new service providing children in crisis with confidential support, guidance and a route to safety – and as the campaign continues, we tell Mary’s story and why she has never been forgotten.

Mary disappeared on New Year’s Eve 1959 after leaving her family home in West Ham, east London, to attend a work party. The now 82-year-old was never seen or heard from again, but her family’s fight for answers persisted for decades.

Her siblings never stopped searching for the truth, yet both of her sisters died without ever knowing what happened to her.

In 2021, Mary’s younger sister Brenda wrote a letter hoping to reach her: “I am writing this in the hope you may read this letter. I have missed you so much over the years, and I have been looking for you for many years and will continue to do so.

“I have so much I want to share with you, but for now I want you to know I love you and I would love for you to make contact with me and we can take things at your own pace.”