This paper presents a method for operational leakage reduction and security enhancement of water distribution networks using optimised on-line control of pressure reducing valves and variable speed pumps. An earlier algorithm which uses valve control only has been extended to solve the combined problem of controlling valves and variable speed pumps, and furthermore, new hydraulic constraints have been added. The problem is formulated as an optimisation of the system pressure profile subject to the network hydraulic balance and system operational constraints. A solution technique based on successive linear programming is described. Sparsity techniques are employed to achieve computational efficiency. The effectiveness of the pressure control scheme is illustrated using an example network.