Both ruby laser ( 300 points ) and NdYAG laser ( 19 points ) Thomson scattering systems are used on MAST. Fast nonlinear optical switching shunts laser beams from the four 50 Hz NdYAG lasers to obtain coaxial plasma illumination. The technique allows for future expandability to many laser systems. The ruby laser system is used in parallel. A broadband thin-plate polariser, based on nanotechnology, has been incorporated in the collection optics. It has a wide field of view and it almost halves the detected laser stray light and plasma background for both laser spectral regions. This allows much of the collection optics to function effectively in both spectral regions simultaneously.