A polymeric catalyst comprising repeating subunits of the formula I: wherein R 1, R 2, R 3 and R 4 are independently selected from phenyl and C 4-8 cycloalkyl, the latter two groups being unsubstituted or substituted, where possible, with 1, 2, 3, 4, or 5 groups independently selected from C 1-6 alkyl, OC 1-6 alkyl and halo; is a binaphthyl group or a derivative of a binaphthyl group, wherein the derivative of the binaphthyl group is selected from a binaphthyl group wherein the naphthalene ring is partially reduced, or a binaphthyl group in which the naphthalene ring is condensed with a saturated hydrocarbon ring, wherein each of the binaphthyl group or the derivative of the binaphthyl group is unsubstituted or substituted with one or more groups independently selected from C 1-6 alkyl, OC 1-6 alkyl and halo; R 5, R 6, R 7 and R 8 are independently selected from H, C 1-6 alkyl, OC 1-6 alkyl and halo, or R 5 and R 6 and/or R 7 and R 8 are =O, or one of R 5 and R 6 is linked to one of R 7 and R 8 to form, together with the atoms to which they are attached and the atoms connecting them, a monocyclic, bicyclic or tricylic ring system, R 5, R 6, R 7 and R 8 in each methylene unit is the same or different, and means the double bond attached to this bond is in the cis or trans configuration, if applicable; m and n are, independently, an integer between and including 0 and 10; p is an integer between and including 1 and 14; and X is an anionic ligand. R 1, R 2, R 3 and R 4 are independently selected from phenyl and C 4-8 cycloalkyl, the latter two groups being unsubstituted or substituted, where possible, with 1, 2, 3, 4, or 5 groups independently selected from C 1-6 alkyl, OC 1-6 alkyl and halo; is a binaphthyl group or a derivative of a binaphthyl group, wherein the derivative of the binaphthyl group is selected from a binaphthyl group wherein the naphthalene ring is partially reduced, or a binaphthyl group in which the naphthalene ring is condensed with a saturated hydrocarbon ring, wherein each of the binaphthyl group or the derivative of the binaphthyl group is unsubstituted or substituted with one or more groups independently selected from C 1-6 alkyl, OC 1-6 alkyl and halo; wherein the derivative of the binaphthyl group is selected from a binaphthyl group wherein the naphthalene ring is partially reduced, or a binaphthyl group in which the naphthalene ring is condensed with a saturated hydrocarbon ring, wherein each of the binaphthyl group or the derivative of the binaphthyl group is unsubstituted or substituted with one or more groups independently selected from C 1-6 alkyl, OC 1-6 alkyl and halo; R 5, R 6, R 7 and R 8 are independently selected from H, C 1-6 alkyl, OC 1-6 alkyl and halo, or R 5 and R 6 and/or R 7 and R 8 are =O, or one of R 5 and R 6 is linked to one of R 7 and R 8 to form, together with the atoms to which they are attached and the atoms connecting them, a monocyclic, bicyclic or tricylic ring system, R 5, R 6, R 7 and R 8 in each methylene unit is the same or different, and means the double bond attached to this bond is in the cis or trans configuration, if applicable; m and n are, independently, an integer between and including 0 and 10; p is an integer between and including 1 and 14; and X is an anionic ligand.