1. A lighting device comprising a transmissive body housing a luminous arrangement, and a fitting cooperating with the transmissive housing, said luminous arrangement comprising a single piece flexible carrier mounted on a support structure, wherein the support structure is mounted inside the fitting to form a support assembly; the flexible carrier comprising:a first tubular end portion enveloping a first region of the support structure;
a second tubular end portion enveloping a second region of the support structure, the first region being spatially separated from the second region axially; and
a plurality of strip-shaped portions formed by a plurality of incisions in a central section of the flexible carrier, the strip-shaped portions axially extending from the first tubular end portion to the second tubular end portion, each of said strip-shaped portions carrying a plurality of solid state lighting elements;
wherein the central section is mounted on the support structure in a rolled state and has a parallelogram shape in an unrolled state, and the incisions extend in parallel with a side edge of the parallelogram shape such that each of the strip-shaped portions spirals from the first tubular end portion to the second tubular end portion when the flexible carrier is in the rolled state; and
wherein the support assembly comprises a sub-assembly configured to exert an axial force that biases the first tubular end portion and the second tubular end portion axially together, such that the strip-shaped portions are forced to radially extend between the first tubular end portion and the second tubular end portion, after or during mounting the support assembly into the transmissive housing.