A roller blind including a sheet element secured at one end to a roller tube mounted for rotation, and secured at its opposite end to a fixed element located adjacent to the roller tube such that the sheet element defines a return portion located between the two ends; and a roller blind bottom bar (4) located within the return portion, wherein the roller blind bottom bar includes a tubular body and an end cap (2) carried by each end of the tubular body, the end caps including a proximal portion (6) located adjacent to the tubular body, a distal portion (8) spaced from the tubular body, and an outwardly flared portion (10) located between the proximal and distal portions such that the end cap flares outwards from the proximal portion to the distal portion.