Hugh MacPhail was the president of the Consistorial Court of Discipline. He was celebrated as the youngest president in the history of the Consistorial Court of Discipline, a position that the holder keeps for life. He subsisted on bread, fruit and water only and exercised with the intensity of a world-class athlete.
The extent of MacPhail's fanatical dread of Dust was clearly seen when he proclaimed, "...if in order to destroy Dust we also have to destroy the Oblation Board, the College of Bishops, every single agency by which the Holy Church does the work of the Authority — then so be it ... better a world with no church and no Dust than a world where every day we have to struggle under the hideous burden of sin."
It was MacPhail who proposed Lyra's assassination and sent another member of the Court, Father Gomez, to find the child and kill her. McPhail directed one of the younger priests to steal Coulter's locket to get a strand of Lyra's hair for the guidance mechanism of a bomb that he had had built for the purpose of tracking and killing Lyra.
He decided to punish Coulter for not bringing Lyra to him when she had the chance by severing her from her dæmon, thereby releasing the energy needed to launch the bomb intended to kill Lyra. When Coulter escaped he chose what he considered to be martyrdom, conducting his own intercision, and died.