  Using XMM we detect faint unresolved X-ray emission from the Compact Steep
Spectrum radio galaxy 3C303.1. We detect a thermal component at kT = 0.8 keV
which seems likely to be produced in the ISM of the host galaxy. There is
evidence for a second component in the spectrum whose nature is currently
ambiguous. Plausible hypotheses for the second component include (1) hot gas
shocked by the expansion of the radio source, and (2) Synchrotron self-Compton
emission from the southern radio lobe if the magnetic field is below the
equipartition value by a factor of about 3.5.
