a polymer of ethylene and at least one alpha olefin having at least 5 , carbon atoms obtainable by a continuous gas phase polymerization using supported catalyst of an activated molecularly discrete catalyst such as a metallocene in the substantial absence of an aluminum alkyl based scavenger which polymer has a melt index as herein defined of from 0 . 1 to 15 ; a compositional distribution breadth index as defined herein of at least 70 %, a density of from 0 . 910 to 0 . 930 g / ml ; a haze value as herein defined of less than 20 %; a melt index ratio as herein defined of from 35 to 80 ; an averaged modulus as herein defined of from 20 000 to 60 000 psi and a relation between m and the dart impact strength in g / mil complying with the formula : dis ≧ 0 . 8 ×].