A powered surgical instrument comprising: a handle portion; a body portion extending distally from the handle portion and defining a first longitudinal axis (A-A); an articulating tool assembly defining a second longitudinal axis (B-B) and having a proximal end, the articulating tool assembly disposed at a distal end of the body portion and being movable from a first position in which the second longitudinal axis is substantially aligned with the first longitudinal axis to at least a second position in which the second longitudinal axis is disposed at an angle with respect to the first longitudinal axis; and an articulation mechanism configured to articulate the articulating tool assembly, wherein the articulation mechanism includes: an articulation motor operatively coupled to the articulating tool assembly; a controller electrically coupled to the articulation motor and configured to control operation of the motor; and at least one delayed activation switch (174a, 174b) coupled to the controller, characterised in that the at least one delayed activation switch must be engaged continuously for a predetermined period of time that is tracked by the controller, whereby once the engagement period exceeds the predetermined period of time, the controller activates the articulation motor to impart an articulating motion to the end effector, thereby preventing accidental activation of the articulation mechanism. a handle portion; a body portion extending distally from the handle portion and defining a first longitudinal axis (A-A); an articulating tool assembly defining a second longitudinal axis (B-B) and having a proximal end, the articulating tool assembly disposed at a distal end of the body portion and being movable from a first position in which the second longitudinal axis is substantially aligned with the first longitudinal axis to at least a second position in which the second longitudinal axis is disposed at an angle with respect to the first longitudinal axis; and an articulation mechanism configured to articulate the articulating tool assembly, wherein the articulation mechanism includes: an articulation motor operatively coupled to the articulating tool assembly; a controller electrically coupled to the articulation motor and configured to control operation of the motor; and at least one delayed activation switch (174a, 174b) coupled to the controller, characterised in that the at least one delayed activation switch must be engaged continuously for a predetermined period of time that is tracked by the controller, whereby once the engagement period exceeds the predetermined period of time, the controller activates the articulation motor to impart an articulating motion to the end effector, thereby preventing accidental activation of the articulation mechanism. an articulation motor operatively coupled to the articulating tool assembly; a controller electrically coupled to the articulation motor and configured to control operation of the motor; and at least one delayed activation switch (174a, 174b) coupled to the controller, characterised in that the at least one delayed activation switch must be engaged continuously for a predetermined period of time that is tracked by the controller, whereby once the engagement period exceeds the predetermined period of time, the controller activates the articulation motor to impart an articulating motion to the end effector, thereby preventing accidental activation of the articulation mechanism.