This paper presents a controller design methodology for a class of uncertain, multivariable, regulating systems required to maintain operating conditions within small tolerances despite a vector step disturbance. Furthermore, each control effort is limited by its hardware, namely the actuator outputs are limited in magnitude and response speed. The design methodology is a frequency domain approach and is based on single loop design. A Gauss elimination technique facilitates the various design steps. The specific class of systems addressed are those which can be modelled as square, multivariable systems with structured (i.e. parametric) and/or unstructured uncertainty. One restriction imposed on the system is that it must be invertible for all plant parameter combinations. The key features of this methodology include (i) the role played by loop interaction in achieving overall system performance; (ii) the ability to accommodate both parametric and unstructured uncertainty; (iii) the explicit consideration of transmission zeros; and (iv) the incorporation of controller constraints. As will be seen, focusing the design efforts on the loop interactions at a local level will allow individual bandwidths to be specified thereby providing an economical design.