  We present 7-180micron photometry of a sample of hyperluminous infrared
galaxies (HyLIGs) obtained with the photometer and camera mounted on the
Infrared Space Observatory. We have used radiative transfer models of obscured
starbursts and dusty torii to model their spectral energy distributions (SEDs).
We find that F00235+1024, F14218+3845 and F15307+3252 require a combination of
starburst and AGN components to explain their mid to far-infrared emission,
while for TXS0052+471 a dust torus AGN model alone is sufficient. For
F00235+1024 and F14218+3845 the starburst component is the predominant
contributor whereas for F15307+3252 the dust torus component dominates. The
implied star formation rates (SFR) for these three sources estimated from their
infrared luminosities are $\dot{M}_{*,all} > 3000M_{\odot}yr^{-1}h_{50}^{-2}$
and are amongst the highest SFRs estimated to date. We also demonstrate that
the well-known radio-FIR correlation extends into both higher radio and
infrared power than previously investigated. The relation for HyLIGs has a mean
q value of ~1.94. The results of this study imply that better sampling of the
IR spectral energy distributions of HyLIgs may reveal that both AGN and
starburst components are required to explain all the emission from the NIR to
the sub-millimetre.
