A surgical access port and assembly are disclosed for providing access for a medical instrument into an intracorporeal cavity of a patient undergoing surgery. The access port comprises a cannula and a first passage which extends along the cannula and along which a medical instrument is arranged to pass, the passage comprising a first entrance portion disposed at a proximal region the of the cannula and a first exit portion disposed at a distal region of the cannula. The cannula further comprises a second passage which extends along the cannula and along which an electrode is arranged to pass, the second passage comprising a second entrance portion disposed at a proximal region of the cannula and a second exit portion disposed at a distal region of the cannula. The first exit portion of the first passage and the second exit portion of the second passage diverge along the cannula in a direction which is from the proximal end to the distal end of the cannula, to suitably locate the electrode with respect to a medical instrument.