  We present submillimetre continuum observations of a sample of some of the
highest redshift quasars currently known, made with the SCUBA bolometer array
on the JCMT. The median redshift of the sample is 5.3. Two z>5 objects are
strong (6 sigma) detections, with S(850um)>10mJy. A firm (5 sigma) detection is
obtained for the z=5.7 quasar SDSS J1044-0125; and SDSS J1306+0356, at z=6.0,
is detected with a signal-to-noise approx. 4. For the remainder of the sample
we have obtained sensitive (sigma=1.5mJy) upper limits. Submm spectral indices
measured for two of the sources are consistent with thermal reradiation from
dust, rather than from synchrotron emission. Sensitive 450um upper limits imply
that the dust is cool,suggesting large dust masses only 1Gyr after the Big
Bang.
