The present invention relates to a process for the 
polymerization and copolymerization of 1-olefins and to a catalyst to be used in said process wherein the catalyst comprises (1) a complex having formula (I) wherein M is Fe[II], Fe[III], Co[I], Co[II], Co[III], Mn[I], Mn[II], Mn[III], Mn[IV], Ru[II], Ru[III] or Ru[IV]; X represents an atom or group covalently or ionically bonded to the 
metal M; T is the 
oxidation state of the 
metal; b is the valency of the atom or group X; and R 1 to R 7 are each independently selected from 
hydrogen, 
halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR' 3 where each R' is independently selected from 
hydrogen, 
halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl; and when any two or more of R 1 to R 7 are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents; (2) an activator which is an alkylalumoxane; and (3) a support material, wherein the 
atomic ratio of 
aluminium in the alkylalumoxane (2) to 
transition metal M in (1) is from 6:1 to 25:1.