Abstract: A tape laying head configured to lay a tow material on a mould in the construction of a composite structure, the tape laying head including: a shearing mechanism configured to receive tow material from a tow supply and to steer the tow material by applying shear deformation to the tow material between a pair of shear boundaries defined by the shearing mechanism, the shearing mechanism being further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a transverse component with respect to the tow material during steering of the tow material; and a tension control system configured to control the transverse component of the driving force acting on the tow material to be equal to or less than a maximum transverse frictional force associated with the shearing mechanism by varying a tensioning force applied to the tow material by the tension control system and monitoring the driving force.