A screwdriver for inserting and removing socket head screws with tips 1 which can be locked into the screw socket. The screwdriver has a central blade 2 which can be pushed through the centre of the outer shaft 5 and between the two or more tips, forcing the tips outwards so that they engage with the walls of the screw socket. On retraction of the central blade, the tips return to the neutral position and the screwdriver can be removed. The driving blade is actuated by a thumb piece 6 and toggle mechanism 8. The nosepiece 9 holding the tips is free floating and able to rotate independently of the driving shaft. The tips may have lateral ledges or ridges to assist in aligning the tips into the screw head. The screwdriver can also be used for surgical screws. In various embodiments the screwdriver can be used for large diameter socket screws, and can have many alternative nose piece shapes.
