A multimodal polyethylene copolymer suitable for use in cable insulation comprising: (III) 45 to 55 wt % of a lower molecular weight component which is an ethylene copolymer of ethylene and at least one C3-12 alpha olefin comonomer, said LMW component having a density of 940 to 962 kg/m3 and an MFR2 of 50 to 500 g/10 min; (IV) 55 to 45 wt % of a higher molecular weight ethylene copolymer component of ethylene and at least one C3-12 alpha olefin comonomer; wherein said multimodal polyethylene copolymer has a density of 940 to 950 kg/m3, an MFR2 of 0.05 to 2.0 g/10 min and preferably at least one of crystallization half time>3.0 mins at 120.5° C., a crystallization half time>5.0 mins at 121° C. or a crystallization half time>10.0 mins at 122° C.