A novel algorithm has been described for the fast calculation of complex molecular weight distributions (MWD) produced in living anionic polymerisation conducted in periodically perturbed continuous stirred lank reactor (CSTR), the predictions of which have been tested experimentally using a limited set of conditions in a computer controlled laboratory-scale polymerisation reactor (Part I and II: Gosden et al., 1995a and 1997a). In this work, the prospect of using the algorithm for the control of flow reactors is explored giving particular attention to the square-pulse feed strategies and reaction mechanism which have been used previously to demonstrate the influence of reactor feed conditions on polymer molecular weight distribution. Both initiator and monomer pulsed feeds are examined the main variables being pulse width, pulse period, the phase of initiator pulse relative to monomer pulse, mean residence time, average feed concentration of monomer and initiator, and the rate constants of initiation and propagation. The influence of these factors on the average molecular weight, molecular weight distribution and dispersity index of the product is considered. The use of pulsed feeds to a CSTR for tailoring polymer molecular weight distribution are briefly considered as are the ways in which the algorithm may be extended to other polymerisation chemistries, notably to pulsed laser free-radically initiated polymerisation (PLP) processes.