...with a liquid swelling medium prior to use of the catheter and a catheter package (7, 16, 29, 34, 42, 46, 51, 51´) made of a gas impermeable material formed by a multiple layer thermoplastic film material comprising aluminium, the package having a cavity (11, 18, 39, 48, 53) for accommodation of the catheter (1, 58, 69), wherein the cavity accommodates 2 to 30 ml of said liquid swelling medium for provision...