Bi0.7La0.3FeO3 has received extensive attention in the past years, since this compound exhibits simultaneously ferroelectricity and ferromagnetism at room temperature. Despite the research undertaken in this compound, a number of questions including: the understanding of the mechanisms associated with the ferroelectric and magnetic phase transitions as well as the correlations between structure, magnetism and ferroelectricity, are still under debate. The aim of this proposal is to perform temperature dependent high resolution powder neutron diffraction in Bi0.7La0.3FeO3, in order to study its crystalline and magnetic structures. From the experimental results, we aim at determining the symmetry and the temperature dependence of wavevector of the modulated phases, the structural distortions associated with the ferroelectric and ferromagnetic phase transitions, and evaluate spin-lattice co