What was the "creepy voice" heard whispering on ITV's live coverage of the Queen's state funeral?

TV viewers were left "creeped out" after what has been described as a "ghostly" woman's voice interrupting ITV's live coverage of Queen Elizabeth II's funeral. The whispering woman can be heard during presenter Tom Bradby's commentary during an aerial shot of the Queen's hearse heading out into West London. The disembodied voice whispers something to the effect of "the death is irreversible and the fact that she's trapped ..." and then cuts off. The moment can be heard on ITV Hub's ceremonial coverage at 4hours and 28 minutes.