Abstract: A process for producing a chromium-based catalyst for the production of polyethylene, the process comprising providing a silica support having a surface area of at least 380 m2/g and a pore volume of at least 1.5 ml/g; impregnating the silica support with a liquid including a source of aluminum ions and a source of phosphate ions; neutralizing the resultant impregnated support with a neutralizing agent to provide a pH greater than 7 for the resultant neutralized support whereby aluminum phosphate forms in pores of the silica support; and, at any stage in the method, impregnating the silica support with a chromium component.