A solution polymerization process for the obtainment of a copolymer containing from 30 up to 91 % by mol of propylene units and being fully soluble in a polymerization medium, said polymerization medium being a mixture of monomers in the presence of an inert carbon solvent, and in a concentration range of 5 to 50% by weight, comprising contacting under polymerization conditions at a polymerization temperature comprised between 89 and 120 °C, propylene and at least ethylene or an alpha olefin of formula CH 2 =CHT wherein T is a C 2 -C 20 alkyl radical, in the presence of a catalyst system obtainable by contacting: a) at least a metallocene compound of formula and b) alumoxane or a compound capable of forming an alkyl metallocene cation; wherein in the metallocene compound of formula: M is an atom of a transition metal selected from those belonging to group 3, 4, or to the lanthanide or actinide groups in the Periodic Table of the Elements; X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OR'O, OSO 2 CF 3, OCOR, SR, NR 2 or PR 2 group wherein R is a linear or branched, cyclic or acyclic, C 1 -C 40 -alkyl, C 2 -C 40 alkenyl, C 2 -C 40 alkynyl, C 6 -C 40 -aryl, C 7 -C 40 -alkylaryl or C 7 -C 40 -arylalkyl radical; optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; and R' is a C 1 -C 20 -alkylidene, C 6 -C 20 -arylidene, C 7 -C 20 -alkylarylidene, or C 7 -C 20 -arylalkylidene radical; L is a divalent bridging group selected from C 1 -C 20 alkylidene, C 3 -C 20 cycloalkylidene, C 6 -C 20 arylidene, C 7 -C 20 alkylarylidene, or a C 7 -C 20 arylalkylidene radicals, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements, or it is a silylidene radical containing up to 5 silicon atoms; R 1 is a linear C 1 -C 40 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; R 2 and R 3, equal to or different from each other, are C 1 -C 40 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or R 2 and R 3, are part of 4-7 membered ring condensed to the benzene ring of the indenyl moiety; said ring optionally containing heteroatoms belonging to groups 13-16 of the Periodic Table of the Elements; the valence of each atom forming said ring being filled with R 18 radicals, wherein R 18, equal to or different from each other, are hydrogen atoms or C 1 -C 40 hydrocarbon radicals; R 4 is a hydrogen atom or a C 1 -C 40 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; W is an aromatic 5 or 6 membered ring that can contain heteroatoms belonging to groups 13-16 of the Periodic Table of the Elements; the valence of each atom of said ring is substituted with hydrogen atom or it can optionally be substituted with R 5 groups wherein R 5, equal to or different from each other, are C 1 -C 40 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements. a) at least a metallocene compound of formula and b) alumoxane or a compound capable of forming an alkyl metallocene cation; M is an atom of a transition metal selected from those belonging to group 3, 4, or to the lanthanide or actinide groups in the Periodic Table of the Elements; X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OR'O, OSO 2 CF 3, OCOR, SR, NR 2 or PR 2 group wherein R is a linear or branched, cyclic or acyclic, C 1 -C 40 -alkyl, C 2 -C 40 alkenyl, C 2 -C 40 alkynyl, C 6 -C 40 -aryl, C 7 -C 40 -alkylaryl or C 7 -C 40 -arylalkyl radical; optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; and R' is a C 1 -C 20 -alkylidene, C 6 -C 20 -arylidene, C 7 -C 20 -alkylarylidene, or C 7 -C 20 -arylalkylidene radical; L is a divalent bridging group selected from C 1 -C 20 alkylidene, C 3 -C 20 cycloalkylidene, C 6 -C 20 arylidene, C 7 -C 20 alkylarylidene, or a C 7 -C 20 arylalkylidene radicals, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements, or it is a silylidene radical containing up to 5 silicon atoms; R 1 is a linear C 1 -C 40 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; R 2 and R 3, equal to or different from each other, are C 1 -C 40 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or R 2 and R 3, are part of 4-7 membered ring condensed to the benzene ring of the indenyl moiety; said ring optionally containing heteroatoms belonging to groups 13-16 of the Periodic Table of the Elements; the valence of each atom forming said ring being filled with R 18 radicals, wherein R 18, equal to or different from each other, are hydrogen atoms or C 1 -C 40 hydrocarbon radicals; R 4 is a hydrogen atom or a C 1 -C 40 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; W is an aromatic 5 or 6 membered ring that can contain heteroatoms belonging to groups 13-16 of the Periodic Table of the Elements; the valence of each atom of said ring is substituted with hydrogen atom or it can optionally be substituted with R 5 groups wherein R 5, equal to or different from each other, are C 1 -C 40 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements.