Abstract The transverse mechanical behaviour of a unidirectional continuous carbon-fibre-reinforced/epoxy (CFRP) composite has been studied in detail. Carbon fibres at six different levels of an oxidative fibre surface treatment were converted into prepreg with a high-performance TGDDM/DDS epoxy matrix which has been the subject of an earlier study (Part 1). Laminates of  16 configuration were used to measure elastic properties and failure strengths in tensile and flexural loading modes. Intra-laminar fracture toughness values were measured by using compact tension specimens. The distribution of tensile transverse strengths within the CFRP laminates have been studied using hybrid sandwich laminates consisting of 0° GRP outer plies encompassing a core of 90° CFRP. CFRP cores consisting of both 8 and 16 plies of 0% (untreated) and 100% (standard treatment) fibre treatment levels have been studied. These laminates were tested in tension leading to the formation of multiple transverse cracks within the CFRP core, enabling Weibull strength distribution charts to be constructed. These data have been used in conjunction with similar bulk resin sandwich laminate data to compare strength and failure mechanisms. Finally, scanning electron microscopy has been used for post-morten examination of the fracture surfaces. The results are used to draw conclusions about the operative failure mechanisms and it is suggested that embedded defects only have a secondary role in formation of the critical failure sites.