An irrigation system has an elongated irrigation tube subdivided by an integrally formed internal partition into a first lumen and a second lumen. At one end of the tube, a supply connection connects a water supply to the first lumen while at the other a termination arrangement defines a flow path from the first lumen to the second lumen. There is thus defined a water flow path which passes from the supply connection along the first lumen and then via the termination arrangement back along the second lumen. Water is released either by openings spaced along the tube connecting to the second lumen, or by the use of porous material for the irrigation tube. The partition is preferably flexible so that, under the pressure differentials occurring during use, an effectively conical flow path is created.