Disclosed is apparatus comprising a wound dressing 15 connected to a fluid container 11 via a pump 3, wherein the wound dressing is in communication with a mechanical pressure control valve 13, the fluid container is provided with an inlet 2 and a vent outlet 4, see figure 1. The fluid container is a flexible fluid container comprising at least two layers of film 21, 23 with an integrated vent 29, preferably a microporous fluid separator or hydrophobic membrane, which divides the container into at least two internal compartments, permitting gas flow between the compartments from the inlet 19 to the outlet 31 but preventing fluid flow. Absorbent polymeric material 25, 27 may act as a spacer. Other apparatus provided comprises a means for detecting the level of fluid within a wound fluid container, comprising a restraining strap, plate or rigid housing. In particular the strap may comprise a pressure sensitive switch, with electrical contacts which break a detection circuit on expansion of the container.
