The present invention provides an accumulator (20) comprising a housing (21), an inner portion (23) within the housing, and a zone (27) defined between the housing and the inner portion for fluid communication with a driving fluid of a fluid-powered system whereby the inner portion is exposed to the driving fluid received within the zone. The inner portion comprises a resiliently deformable solid mass (31), wherein at least a portion of the mass is deformable in response to fluid pressure in the zone exceeding a prescribed level thereby to provide pressure relief. The deformable portion resiliently rebounds in response to fluid pressure in the zone returning to or falling below the prescribed level.