Cairney, 77, and Jones, 58, were on trial at the High Court in Glasgow accused of murdering Margaret, when she was 19, at the home they shared at Seacroft, Main Road, Inverkip, between December 18, 1999 and January 5, 2000.
They deny murdering her by means unknown and also deny claiming £182,000 in benefits fraud by pretending she was alive.
The trial, which was in its third week, was halted today.
Judge Lord Matthews said: “I will desert the trial pro loco et tempore, As a result of circumstances we can’t proceed. It is highly unfortunate all this has arisen.
No explanation was given in court for the trial collapsing, but Lord Matthews said that it was no fault of either the prosecution or defence counsel.
Prosecutor Iain McSporran QC said: “I move for the trial to be deserted and for a fresh preliminary hearing and fresh trial to be set. I also think a brand new indictment.”
Defence QC Thomas Ross applied for bail for his client Cairney and this will be decided today/tomorow (Fri).