1. A bracket for supporting a shelf or the like from an upright cylindrical support, said bracket comprising an elongate arm upon which a shelf or the like is supported horizontally in use of the bracket and a clamping head arranged at one end of said arm for attaching the bracket to the said upright cylindrical support, wherein said clamping head comprises a part-cylindrical portion attached to said arm and adapted to lie against part of the circumference of the cylindrical support, a leaf spring member permanently having a natural curvature which is substantially the same as that of said part-cylindrical portion, means for permanently attaching one end of said leaf spring member to said part-cylindrical portion forming a substantially continuous internal cylindrical surface which lies against the surface of the cylindrical support in use of the bracket, a part-cylindrical member, means for permanently attaching the part-cylindrical member to the other end of said leaf spring member, said partcylindrical member having a curvature substantially the same as that of said part-cylindrical portion, the natural resilience of said spring strip and the length of the latter being such that when said part-cylindrical portion lies against part of the circumference of the cylindrical support the spring strip brings the part-cylindrical member into juxtaposition with another part of the circumference of said support while the spring strip itself lies against an intermediate part of the circumference of said support so that the head surrounds said support, said partcylindrical member having a straight portion which lies adjacent part of said arm when the leaf spring member embraces the support, and securing means for releasably connecting said straight portion and said adjacent part of the arm to clamp the head to the support.