from which users can generate simulation products for comparison with observations. The radio–infrared connection is of immense empirical and theoretical interest for extragalactic surveys, for the identification and follow-up of [*Herschel*]{} sources, and for probing the physics of the far-infrared–radio correlation and its possible evolution. The simulation can nevertheless also serve as a standalone [*Herschel*]{} simulation, for comparison with others such as the phenomenologically-inspired backward evolution models of Valiante et al. (2009) and Pearson & Khan (2009), and the model of Lacey et al. (2009) which is based on a semi-analytical galaxy formation model.

THE ASSIGNMENT OF INFRARED SEDs TO THE RADIO SOURCE POPULATIONS
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The input radio source catalogue was obtained from the $S^{3}$-SEX online database and negative evolution at high redshift was imposed using the ‘default post-processing options’ described in W08. Each radio source was assigned an infrared SED from various template libraries appropriate for star-forming galaxies and AGN, and the output flux density of each infrared model component for each galaxy \[in log(F$_{\rm{\nu}}$(Jy)\] was computed at observed wavelengths of 24, 70, 100, 160, 250, 350, 450, 500, 850, and 1200 . The wavelengths of 24, 70 and 160  are those of the [*Spitzer*]{} MIPS instrument, for which 