This proposal is part of our project to investigate the unusual physics of 5d transition metal oxides (5dTMO).The compound of interest, Pr2Ir2O7, is an important member of the rare earth iridate R2Ir2O7 series. Several enticing theoretical proposals have focused the community's attention on this family; most importantly the prediction of topologically non-trivial electronic states in the bulk (the Weyl-semimetal). R2Ir2O7 exhibit an unusual metal-insulator transition that can be continuously suppressed by variation of the R ion. Pr227 is the critical compound, where this state is only just suppressed. This leaves behind an unprecedented ground state with negligible net magnetisation and a strong remanent anomalous Hall signal. We propose to follow a recent theoretical proposal which called for neutron diffraction to investigate the possibility of spiral magnetic order below 1.7 K.