Process for the manufacture of a solid catalyst composition comprising the steps of (a) feeding a catalyst system into a vessel, wherein the catalyst system (i) comprises (a) a transition metal compound of formula L m R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (IUPAC), 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, and m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a metal (M') of Group 13 of the periodic table (IUPAC), preferably a cocatalyst (Co) comprising a compound of Al, (ii) has (a) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D 3663 of less than 15 m 2 /g, and (iii) is free of silica carrier material and/or MgCl 2 and/or porous polymeric material, and (iv) has a mean particle size in the range of 5-200 μm, (b) feeding at least one olefin monomer, preferably at least one α-olefin monomer, being gaseous into the vessel, (c) operating the vessel under such conditions that the at least one olefin monomer is polymerized by the catalyst system, producing thereby a solid catalyst composition comprising a polymer matrix in which the solid catalyst system is dispersed, (d) terminating the polymerization of step (c) when the weight ratio of the polymer matrix and the catalyst system [weight polymer matrix /weight catalyst system] in the solid catalyst composition is from 1.0 to 6.0. (a) feeding a catalyst system into a vessel, wherein the catalyst system (i) comprises (a) a transition metal compound of formula L m R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (IUPAC), 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, and m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a metal (M') of Group 13 of the periodic table (IUPAC), preferably a cocatalyst (Co) comprising a compound of Al, (ii) has (a) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D 3663 of less than 15 m 2 /g, and (iii) is free of silica carrier material and/or MgCl 2 and/or porous polymeric material, and (iv) has a mean particle size in the range of 5-200 μm, (i) comprises (a) a transition metal compound of formula L m R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (IUPAC), 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, and m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a metal (M') of Group 13 of the periodic table (IUPAC), preferably a cocatalyst (Co) comprising a compound of Al, (a) a transition metal compound of formula L m R n MX q wherein "M" is a transition metal of anyone of the groups 3 to 10 of the periodic table (IUPAC), 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, and m+q is equal to the valency of the transition metal, and (β) a cocatalyst (Co) comprising a metal (M') of Group 13 of the periodic table (IUPAC), preferably a cocatalyst (Co) comprising a compound of Al, (ii) has (a) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D 3663 of less than 15 m 2 /g, and (iii) is free of silica carrier material and/or MgCl 2 and/or porous polymeric material, and (iv) has a mean particle size in the range of 5-200 μm, (a) a porosity measured according to ASTM 4641 of less than 1.40 ml/g, and/or (β) a surface area measured according to ASTM D 3663 of less than 15 m 2 /g, and (iii) is free of silica carrier material and/or MgCl 2 and/or porous polymeric material, and (iv) has a mean particle size in the range of 5-200 μm, (b) feeding at least one olefin monomer, preferably at least one α-olefin monomer, being gaseous into the vessel, (c) operating the vessel under such conditions that the at least one olefin monomer is polymerized by the catalyst system, producing thereby a solid catalyst composition comprising a polymer matrix in which the solid catalyst system is dispersed, (d) terminating the polymerization of step (c) when the weight ratio of the polymer matrix and the catalyst system [weight polymer matrix /weight catalyst system] in the solid catalyst composition is from 1.0 to 6.0.