A model of ion implantation in diamond with an energy of 1 MeV per nucleon is formulated taking into account the two effects : (i) ion channelling through latent tracks, and (ii) ion charge state fluctuations on the basis of a set of the Boltzmann and Fokker-Planck transport equations. Comparison with the experimental data on the implantation of Ni and Xe ions in diamond leads to the conclusion that these effects are essential to the accurate calculation of the depth distributions of impurity and defects at the high energy ion implantation.