Solid catalyst composition comprising a polymer matrix and distributed therein a solid catalyst system, wherein (a) the solid catalyst system (i) has (α) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D3663 of less than 15 m 2 /g, (ii) comprises (α) a transition metal compound of formula L n R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (ICTPAC), each "X" is independently a monovalent anionic σ-ligand, each "L" is independently an organic ligand which coordinates to the transition metal, "R" is a bridging group linking two organic ligands, said organic ligands and said bridging groups do not comprise polymerizable olefinic groups, "m" is 2 or 3, "n" is 0, 1 or 2, "q" is 1,2 or 3, m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a compound of Al, and (iii) is free of silica carrier material and MgCl 2, and (b) the weight ratio of the polymer matrix and the catalyst system [weight polymer matrix /weight catalyst system] in the solid catalyst composition is in the range of 1.0 to 6.0. (a) the solid catalyst system (i) has (α) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D3663 of less than 15 m 2 /g, (ii) comprises (α) a transition metal compound of formula L n R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (ICTPAC), each "X" is independently a monovalent anionic σ-ligand, each "L" is independently an organic ligand which coordinates to the transition metal, "R" is a bridging group linking two organic ligands, said organic ligands and said bridging groups do not comprise polymerizable olefinic groups, "m" is 2 or 3, "n" is 0, 1 or 2, "q" is 1,2 or 3, m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a compound of Al, and (iii) is free of silica carrier material and MgCl 2, and (i) has (α) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D3663 of less than 15 m 2 /g, (α) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D3663 of less than 15 m 2 /g, (ii) comprises (α) a transition metal compound of formula L n R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (ICTPAC), each "X" is independently a monovalent anionic σ-ligand, each "L" is independently an organic ligand which coordinates to the transition metal, "R" is a bridging group linking two organic ligands, said organic ligands and said bridging groups do not comprise polymerizable olefinic groups, "m" is 2 or 3, "n" is 0, 1 or 2, "q" is 1,2 or 3, m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a compound of Al, and (α) a transition metal compound of formula L n R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (ICTPAC), each "X" is independently a monovalent anionic σ-ligand, each "L" is independently an organic ligand which coordinates to the transition metal, "R" is a bridging group linking two organic ligands, said organic ligands and said bridging groups do not comprise polymerizable olefinic groups, "m" is 2 or 3, "n" is 0, 1 or 2, "q" is 1,2 or 3, m+q is equal to the valency of the transition metal, and "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (ICTPAC), each "X" is independently a monovalent anionic σ-ligand, each "L" is independently an organic ligand which coordinates to the transition metal, "R" is a bridging group linking two organic ligands, said organic ligands and said bridging groups do not comprise polymerizable olefinic groups, "m" is 2 or 3, "n" is 0, 1 or 2, "q" is 1,2 or 3, m+q is equal to the valency of the transition metal, (β) a cocatalyst (Co) comprising a compound of Al, and (iii) is free of silica carrier material and MgCl 2, and (b) the weight ratio of the polymer matrix and the catalyst system [weight polymer matrix /weight catalyst system] in the solid catalyst composition is in the range of 1.0 to 6.0.