 From 1999 to 2013, MAST ran 30471 plasmas (in pulses up to 0.5 sec).It confirmed the increased operating efficiency of spherical tokamaks as shown on START – especially demonstrating a high beta (ratio of plasma pressure to the pressure from the confining magnetic field).MAST also performed valuable experiments on controlling and mitigating instabilities at the edge of the plasma – so-called Edge Localised Modes or ELMs.