The present invention relates to catheters, in particular to catheters for draining fluids from a body cavity or for injecting fluids into a body cavity. A catheter 1 is provided having a first lumen 10 for draining fluids from a body cavity or for injecting a fluid into a body cavity, and a separate, second lumen 11 through which a flexible filament 4, such as a suture, is threaded. The suture is anchored at the proximal end 9 of the catheter 1, extends through the second lumen 11 to the distal portion, exits and re-enters the second lumen via second and third holes 8,7, and returns to the proximal end of the catheter 9, terminating in a free end 5. The suture 4 is threaded such that pulling on the free end 5 deforms the deformable distal portion 3 into a pigtail configuration. The present invention also provides a catheter 1 having a locking mechanism 13 in which the flexible filament 4 used to deform the deformable distal portion 3, such as a suture 4, may be locked in position. Preferably the suture 4 is clamped between a clamping portion and a clamping device 13 to lock the suture 4 in position.
