A surgical instrument comprising: first and second shaft members (110, 120), each defining a proximal end portion (112a, 122a) and a distal end portion (112b, 122b), wherein each of the first and second shaft members includes a handle (114, 124) disposed at the proximal end portion thereof; a pivot member defining a pivot axis, the pivot member pivotably coupling the distal end portions of the first and second shaft members, wherein a gap is defined between the distal end portions of the first and second shaft members proximally of the pivot member; first and second jaw members (210, 220) extending distally from the distal end portions of the respective first and second shaft members, the first and second jaw members positioned distally of the pivot member; and a lockout bar movable between an unlocked position, and a locked position, wherein the lockout bar is disposed within the gap in the locked position, wherein the handles of the first and second shaft members are pivotable relative to one another in directions perpendicular to the pivot axis between a spaced-apart position and an approximated position to pivot the first and second jaw members relative to one another between an open position and a closed position, wherein the handles of the first and second shaft members are yawable relative to one another in directions parallel to the pivot axis between the approximated position and a yawed position to yaw the first and second jaw members relative to one another between the closed position and a cutting position, and wherein, the gap provides clearance to permit yawing of the handles of the first and second shaft members such that, when the lockout bar is disposed in the locked position, yawing of the handles of the first and second shaft members is inhibited, characterised in that the lockout bar is withdrawn from the gap in the unlocked position. first and second shaft members (110, 120), each defining a proximal end portion (112a, 122a) and a distal end portion (112b, 122b), wherein each of the first and second shaft members includes a handle (114, 124) disposed at the proximal end portion thereof; a pivot member defining a pivot axis, the pivot member pivotably coupling the distal end portions of the first and second shaft members, wherein a gap is defined between the distal end portions of the first and second shaft members proximally of the pivot member; first and second jaw members (210, 220) extending distally from the distal end portions of the respective first and second shaft members, the first and second jaw members positioned distally of the pivot member; and a lockout bar movable between an unlocked position, and a locked position, wherein the lockout bar is disposed within the gap in the locked position, wherein the handles of the first and second shaft members are pivotable relative to one another in directions perpendicular to the pivot axis between a spaced-apart position and an approximated position to pivot the first and second jaw members relative to one another between an open position and a closed position, wherein the handles of the first and second shaft members are yawable relative to one another in directions parallel to the pivot axis between the approximated position and a yawed position to yaw the first and second jaw members relative to one another between the closed position and a cutting position, and wherein, the gap provides clearance to permit yawing of the handles of the first and second shaft members such that, when the lockout bar is disposed in the locked position, yawing of the handles of the first and second shaft members is inhibited, characterised in that the lockout bar is withdrawn from the gap in the unlocked position.