This work describes the physical and mechanical characterisation of unidirectional 12 and crossply [(0/90)3/0 "]S flax fibre reinforced composites fabricated in autoclave using a prepreg flax tape impregnated with fire retardant epoxy polymer. Tensile, bending and impact properties are evaluated along the longitudinal and transverse fibre directions. The tensile-tensile fatigue behaviour is characterised along the fibre direction. Physical and specific properties are also assessed to identify the potential characteristics of these bio-based composites for lightweight and secondary loadbearing applications. The robust manufacturing process described in this work, coupled with precision laser cutting, makes this type of composite a promising sustainable material for aircraft, transport and lightweight construction designs.