An expanded polymeric material which consists of at least 200 phr, preferably at least 300 phr, but less than 1000 phr, preferably less than 700 phr ingredients in total, comprising 100 phr of at least one polymer, of which at least one is a sulphur and/or metal oxide crosslinkable elastomer and at least 40 phr, preferably at least 55 phr of at least one polymeric flame retardant, preferably a brominated polymeric flame retardant.