Disclosed is a tool for driving a barbed staple into a workpiece, the tool includes a housing enclosing a power delivery source and a driver blade driven by the power delivery source and comprising an engagement portion configured for engagement with the staple. The tool further includes a nosepiece comprising an aperture providing access for loading a staple into the nosepiece and a passage configured for slidable mounting of the driver blade. In use, the driver blade may be driven along a longitudinal axis of the passage by the power delivery source to engage and drive a staple into a workpiece. Clearances are providing to allow for loading and passage of the barbed staples in the nosepiece and arrangements are provided to maintain the alignment of the staple in the nosepiece to compensate for those clearances.