The study will assess the safety of the vaccinations, and the immune responses to vaccination. Immune responses are measured by tests on blood samples. Volunteers will be infected with malaria by mosquito bites, 12 weeks after the first vaccination. In addition, a group of volunteers not receiving vaccines will also be infected with malaria by the same method. These infection experiments will be used to assess vaccine efficacy: how well the vaccines act to prevent malaria disease. A further single volunteer may also be infected with malaria; this volunteer participated in a previous trial where they received vaccines and was completely protected against malaria disease after infection by mosquito bite.