Data recorded during triaxial rock deformation experiments of Westerly granite in the presence of pressurised pore fluids (water). Data consists of mechanical data (load, displacement, confining pressure) and pore pressure data (up- and downstream pore pressure, upstream intensifier volume, four pore pressure transducers mounted on sample). Contains all data necessary to evaluate the results presented in the paper entitled: 'Dilatancy stabilises shear failure in rock' by Aben and Brantut, submitted to Earth and Planetary Science letters, and available at arXiv (arXiv:2101.10036).