The Mega Ampere Spherical Tokamak (MAST) experiment was a nuclear fusion experiment in operation at Culham, Oxfordshire, United Kingdom from December 1999 to September 2013. It followed the highly successful Small Tight Aspect Ratio Tokamak (START) experiment (1991 - 1998) and is followed by MAST-Upgrade (2016 - ), which re-uses many of MAST's components and services. MAST used the same innovative spherical tokamak design as START, which has shown itself to be more efficient than the conventional toroidal design, adopted by Joint European Torus (JET) and ITER. START proved to exceed even the most optimistic predictions and the purpose of MAST is to confirm the results of its forerunner by using a larger more purpose-built experiment.