An additive composition comprising a polymer and an anti-static additive wherein polymer comprises the following monomer components: (i) one or more compounds of formula wherein R 1 is hydrogen or CH 3; and R 2 is a hydrocarbon group having 6 to 30 carbon atoms and is a straight-chain or branched-chain alkyl group, or an aliphatic or aromatic cyclic group; (ii) one or more compounds of formula wherein R 1 has the meaning above and wherein R 3 is hydrogen or C 1 - C 22 alkyl; each R 4 is independently hydrogen or C 1 - C 22 alkyl; R 5 is hydrogen, a substituted or unsubstituted aliphatic or aromatic cyclic group, or a substituted or unsubstituted straight-chain or branched-chain alkyl group having 1 to 22 carbon atoms; n = 0 or an integer from 1 to 22; and m is an integer from 1 to 30; and (iii) one or more compounds of formula wherein R 6, R 7, R 8, R 9 and R 10 are each independently hydrogen, a straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms which may be substituted or unsubstituted, hydroxyl, NH 2, or wherein two or more of R 6, R 7, R 8, R 9 and R 10 may together form an aliphatic or aromatic ring system, which ring system may be substituted or unsubstituted; wherein anti-static additive comprises (iv) an olefin polysulfone and (v) a polymeric polyamine reaction product of epichlorohydrin and an aliphatic primary monoamine or an N-aliphatic hydrocarbyl alkylene diamine, or the sulfonic acid salt of the polymeric polyamine reaction product; wherein the weight ratio of component (iv) to component (v) is in the range of 100:1 to 1:100; and wherein the weight:weight ratio of the polymer to the anti-static additive in the additive composition is from 1:1 to 500:1, preferably from 50:1 to 300:1, more preferably from 100:1 to 250:1. (i) one or more compounds of formula wherein R 1 is hydrogen or CH 3; and R 2 is a hydrocarbon group having 6 to 30 carbon atoms and is a straight-chain or branched-chain alkyl group, or an aliphatic or aromatic cyclic group; (ii) one or more compounds of formula wherein R 1 has the meaning above and wherein R 3 is hydrogen or C 1 - C 22 alkyl; each R 4 is independently hydrogen or C 1 - C 22 alkyl; R 5 is hydrogen, a substituted or unsubstituted aliphatic or aromatic cyclic group, or a substituted or unsubstituted straight-chain or branched-chain alkyl group having 1 to 22 carbon atoms; n = 0 or an integer from 1 to 22; and m is an integer from 1 to 30; and (iii) one or more compounds of formula wherein R 6, R 7, R 8, R 9 and R 10 are each independently hydrogen, a straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms which may be substituted or unsubstituted, hydroxyl, NH 2, or wherein two or more of R 6, R 7, R 8, R 9 and R 10 may together form an aliphatic or aromatic ring system, which ring system may be substituted or unsubstituted; wherein anti-static additive comprises (iv) an olefin polysulfone and (v) a polymeric polyamine reaction product of epichlorohydrin and an aliphatic primary monoamine or an N-aliphatic hydrocarbyl alkylene diamine, or the sulfonic acid salt of the polymeric polyamine reaction product; wherein the weight ratio of component (iv) to component (v) is in the range of 100:1 to 1:100; and wherein the weight:weight ratio of the polymer to the anti-static additive in the additive composition is from 1:1 to 500:1, preferably from 50:1 to 300:1, more preferably from 100:1 to 250:1.