The temperature dependence of the electrical resistivity of four samples of aluminium has been measured over the range 1.2-4.2K. The samples were annealed at successively higher temperatures between measurements. It has been found that upon annealing the samples, the electron-phonon scattering term increased by about 60% whereas the electron-electron scattering term decreased by about 20-30%. The effect of the successive annealings has been to reduce the dislocation density in the samples. A theoretical analysis has been presented, based on the idea that a reduced dislocation density tended to give an isotropic electron relaxation time. A calculation has been carried out which yields agreement between theory and experiment for both the increase in the electron-phonon scattering term and the decrease in the electron-electron scattering term.