  Understanding the magnetic field sensitivity of Transition Edge Sensors
(TESs) is vital in optimising the configuration of any magnetic shielding as
well as the design of the TESs themselves. An experimental system has been
developed to enable the investigation of the applied magnetic field direction
on TES behaviour, and the first results from this system are presented. In
addition, measurements of the effect of applied magnetic field magnitude on
both supercurrent and bias current are presented. The extent to which the
current theoretical framework can explain the results is assessed and finally,
the impact of this work on the design of TESs and the design of magnetic
shielding is discussed.
