Neutral beam injection in the START spherical tokamakinduces L to H mode transitions in double null divertorconfigurations. The behaviour of the edge poloidalvelocity, electron temperature and density, and edge neutraldensity during the transition are examined. The region encompassing thethermal barrier is investigated with a variety of diagnosticsincluding Doppler spectrometry, Thomson scattering, a BalmerDα camera and magnetics.