The surgical instrument has an end effector controlled by a handle moveable relative to the instrument to move the end effector between two conditions. A latching mechanism is formed of a single integrally formed component arranged to engage with the handle allowing the end effector to be retained in one condition, leaving the users hand free to perform other functions of the instrument. The latching mechanism comprises a protrusion 1120 extending from a moveable handle or trigger into a second handle which has a slideable receiving portion comprising two cam surfaces 1112, 1116 and a notch 1114. To lock the handle, the protrusion interacts with the first cam surface 1112 to push the receiving portion against the bias of a spring element 1104 until the protrusion can be held in the notch 1114. A lock out bar (4602, Figure 46) allows the latching moulding 326 to be moved manually in the handle, so the protrusion only interacts with the second cam surface 1116 and does not lock into the notch 1114.
