This work involves the in-situ synthesis and application of a visible-light activated composite catalyst. The photocatalytic activity of the synthesised photocatalyst was investigated by tracking the degradation of phenol under ultraviolet (UV) and visible light irradiation using a batch reactor set-up. The change in concentration of phenol was determined using a High Performance Liquid Chromatograph (HPLC). The synthesised Ag/AgCl/BiOCl particles were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET). The particles had a flower-like morphology and the XRD confirmed the presence of AgCl and BiOCl phases. A color change from white to purple during the synthesis of the composite catalyst indicated the formation of elemental Ag in the composite. The BET surface area was 6.64 m2g-1. Degradation studies indicated that the Ag/AgCl/BiOCl composite synthesised can be activated by visible light resulting in 52% degradation after 4.5 h at a 0.83 gL-1 catalyst loading.