  The second known outburst of the WZ Sge type dwarf nova GW Lib was observed
in April 2007. We have obtained unique multiwavelength data of this outburst
which lasted ~ 26 days. AAVSO observers recorded the outburst in the optical,
which was also monitored by WASP, with a peak V magnitude of ~ 8. The outburst
was followed in the UV and X-ray wavelengths by the Swift UVOT and XRT
telescopes. The X-ray flux at optical maximum was found to be three orders of
magnitude above the pre-outburst quiescent level, whereas X-rays are normally
suppressed during dwarf nova outbursts. A distinct supersoft X-ray component
was also detected at optical maximum, which probably arises from an
optically-thick boundary layer. Follow-up Swift observations taken one and two
years after the outburst show that the post-outburst quiescent X-ray flux
remains an order of magnitude higher than the pre-outburst flux. The long
interoutburst timescale of GW Lib with no observed normal outbursts support the
idea that the inner disc in GW Lib is evacuated or the disc viscosity is very
low.
