Abstract: A cable entry or exit pipe is formed on a fluid transportation pipeline while in normal operation full of and transporting a fluid under a positive pressure, by a method which comprises the steps: (a) producing two semi-cylindrical shells, one of which carries an oblique branch pipe and has an aperture aligned with the bore of the branch pipe; (b) securing in a fluid tight manner around the pipeline the two shells so as to form a reinforcing collar carrying an oblique branch pipe lying at an acute angle suitable for the entry into and exit from the pipeline of a cable; (c) securing in a fluid tight manner to the free end of the branch pipe an isolating valve; (d) securing in a fluid tight manner to the free side of the isolating valve a fluid tight drilling apparatus equipped with a drilling bit; (e) opening the valve and introducing the drill bit through the opened valve into the branch pipe; (f) rotating and progressively advancing the drill bit into contact with and through the wall of the pipeline section