  We present submillimetre (SCUBA) photometry of a sample of eight
high-redshift (2.5 < z < 3.5) radio quasars from two redshift surveys: the
TEXOX-1000, or TOOT, survey; and the 7C Redshift Survey (7CRS). Unlike the
powerful high-redshift radio sources observed previously in the submillimetre,
these radio sources are typical of those dominating the radio luminosity
density of the population. We detect just two of the TOOT/7CRS targets at 850
microns, and one of these detections is probably due to synchrotron emission
rather than dust. The population represented by the other six objects is
detected in a statistical sense with their average 850-micron flux density
implying that they are similar to low-redshift, far-infrared-luminous quasars
undergoing at most moderate (< 200 solar masses per year) starbursts. By
considering all the SCUBA data available for radio sources, we conclude that
positive correlations between rest-frame far-infrared luminosity, 151-MHz
luminosity and redshift, although likely to be present, are hard to interpret
because of subtle selection and classification biases, small number statistics
and uncertainties concerning synchrotron contamination and K-correction. We
argue that there is not yet any compelling evidence for significant differences
in the submillimetre properties of radio-loud and radio-quiet quasars at high
redshift.
