Little Mary Boyle disappeared in 1977.
A march is taking place in Dublin at 2pm today in a bid to secure an inquest into the disappearance of Mary Boyle 40 years ago.
Mary was last seen on March 18, 1977 near her grandparents house in Ballyshannon, Co Donegal.
Her family have never stopped their search for her and her case now has the unenviable record of being the longest running missing child case in Ireland.
Today's march will assemble at the Garda Ombudsman’s office in Dublin city centre at 2pm and will then make its way to the Department of Justice.