The drive to find novel materials for applications such as data storage has led to a resurgence in research into multiferroic materials. Bismuth ferrite is the most widely studied multiferroic due to its room temperature (anti)ferromagnetic and ferroelectric ordering. However, despite attracting a great deal of attention there is still much debate in the literature as to the nature of the high temperature phases. One problem is that BiFeO3 is prone to decomposition at high temperature making the determination of the high temperature phases difficult. Recently it has been shown that oxygen stabilises BiFeO3 toward peritectic decomposition. It is therefore proposed to conduct high temperature neutron diffraction experiments on BiFeO3 in an oxygen atmosphere with the aim of fully elucidating the high temperature phase and the nature of this phase transition.