This investigation consists of two parallel groups of participants who will follow the same protocol. The aim of the study is to investigate the effects of using Functional Electrical Stimulation/Ankle Foot Orthosis (AFO) or splint as an assistive mobility device over a 12 week period in people with MS who experience foot drop. Patients who are clinically prescribed FES will be invited to participate in the FES arm of the study. Patients who are clinically prescribed an AFO will be invited to participate in the AFO arm. Participants will be asked to make four visits to the gait laboratory at Queen Margaret University. Four weeks before the start of device use (Baseline - 4 weeks), start of device use (Baseline), after 6 weeks and 12 weeks of device use. Participants' walking will assessed using computerised three dimensional motion analysis, which will provide a detailed description of the movements (kinematics) of the lower limbs. Participants will also be asked to carry out a 10 metre walk and a two minute walk. Both gait analysis and the walking performance tests will be carried out with and without an assistive device; apart from their first session where participants will only be assessed without their assistive device.