[en] The Oxford Van de Graaff accelerator has been converted from a heavy ion machine into a single-ended accelerator for electrons. The purpose of the conversion was to provide a relatively intense (∝200 mA) pulsed beam of electrons, in the energy range of 3-4 MeV, for an experiment on the Smith-Purcell radiation. This paper describes the main problems of such a conversion (beam injection and transport through inclined field accelerating tubes, beam stability and electron gun reliability) in a situation where the emphasis was on low cost, short time delay and use of existing components, as far as possible. (orig.)