An elongated electrosurgical instrument (1) comprises a first means (3) for at least cutting tissue of a patient during surgery by application of electrical energy supplied from an electrosurgical generator to a surgical site in response to operating a switch means (5). The instrument has an elongated main body (2) having a first end (7) with a first opening (15) through which the first means (3) protrudes. The first means (3) has a securing part (36) for securing to a holder (33) associated with the first end (7) of the elongated main body (2) of the electrosurgical instrument (1). The securing part (36) of the first means (3) has a first engagement part (37) of a first pentagonal cross-section, and the holder (33) includes a complementarily second engagement part (38) for receiving at least a part of the first engagement part (37).
