The proposed project aims to advance the state-of-the-art of numerical modelling of hydrogen embrittlement (HE). The primary focus and novelty of the project is the description of H transport in modern advanced materials with complex microstructures. This goal will be achieved through development of a multiscale modelling framework, which will enable the extraction and propagation of information pertaining to critical microstructural features from the nanometer level to the macro scale. The key aspect of this modelling effort is the incorporation of atomistically-derived diffusion barriers for critical H trapping sites into continuum and component level models. The gap between the atomistic and continuum hierarchies will be bridged by kinetic Monte Carlo calculations that will provide a basis for derivation of a novel set of equations for H diffusion. These equations will be applied in continuum and component models for boundary conditions representative of those that occur in service. The boundary conditions will be furnished by data collected in-service and from experimental measurements. The outcome of the modelling will be further related to degradation and reliability assessment by the determination of semi-empirical fracture criteria, which will be incorporated into the model at the component level. The modelling will be validated at all levels using advanced experimental techniques. The effectiveness of the proposed simulation framework will be demonstrated by investigating the role of microstructure in three contrasting industrial problems, which have been specified by companies involved in the development and application of advanced materials. The project represents a significant step towards a universal, engineer-oriented software tool for the evaluation of the HE susceptibility of materials and components based on real microstructural information and environmental conditions.