A semi-empirical model, based on concepts used to explain the process of track formation in insulators, has been applied to the experimental observation of improved film adhesion produced by MeV ion irradiation. Good agreement is obtained with experimental data for the system of gold film on native oxides of tantalum. The model uses a single free parameter,e0, which represents the threshold energy density for the process responsible for the improved bonding. The significance of this parameter is discussed in terms of possible ionisation induced interface phenomena.