This trial is designed to evaluate the safety and effectiveness of transplanting nerve stem cells directly into the brains of patients who remain moderately to severely disabled six months to five years following an ischemic stroke. The trial is being conducted at Division of Clinical Neurosciences, Glasgow Southern General Hospital, in conjunction with ReNeuron Limited. Participants will receive different doses of the cells, which have been obtained and expanded from human foetal tissue in the laboratory. Participants will be monitored for complications, as well as changes in their clinical condition. The trial expects to enrol 12 subjects by March 2015.