  The correlation between the far-infrared (FIR) and radio emission is well
established for nearby star forming galaxies. Many applications, in particular
the radio-to-submm spectral index redshift indicator, tacitly assume that the
relation holds well beyond our local neighbourhood, to systems located at
cosmological distances. In order to test this assumption I have constructed a
sample of 20 HDF-N galaxies, all with measured spectroscopic redshifts, and all
detected by both ISO and the WSRT at 15 micron and 1.4 GHz respectively. The
galaxies span a wide range of redshift with a median value of z ~ 0.7. The ISO
15 micron data were k-corrected and extrapolated to the FIR (60 and 100 micron)
by assuming a starburst (M82) spectral energy distribution (SED) for the entire
sample. An initial analysis of the data suggests that the correlation between
the FIR and the radio emission continues to apply at high redshift with no
obvious indication that it fails to apply beyond z ~ 1.3. The sample is
``contaminated'' by at least 1 distant (z=4.4), radio-loud AGN, VLA
J123642+621331. This source has recently been detected by the first deep field
VLBI observations of the HDF-N and is clearly identified as an outlier in the
FIR/radio correlation.
