In this paper we will consider the effect of introducing parallel computers to solve optimisation problems. We briefly highlight four situations where most improvements are likely. We consider the possible interaction of the four classifications with the currently available parallel processing machines. A brief description of one of the parallel systems, ICL DAP, is outlined. We have implemented two parallel (SIMD) algorithms, one for local optimisation and the other for global optimisation, on the ICL DAP. Numerical results, together with the processing times, are reported.