A detailed description of the Langmuir probe system on MAST Upgrade is presented. The system features 850 tile embedded probes, and 40 bespoke electronic modules which each have the capability to drive and acquire data from up to 16 probes in a time multiplexed manner. The system provides spatio-temporal resolved measurements (1 cm and $\\\\sim$1 ms respectively) in the divertor region of ion saturation current, electron temperature and floating potential. The standard interpretation of current-voltage ($IV$) characteristics is to apply a 4 parameter fit, based on unmagnetised probe theory, which includes a linear model for the ion saturation region. To mitigate the effect of the magnetic field, analysis is restricted to the region of the $IV$ characteristic that is sensitive to only the tail of the electron energy distribution function.