  We present results of the first systematic search for submillimetre continuum
emission from z=2, radio-quiet, optically-luminous quasars, using the
SCUBA/JCMT. We have observed a homogeneous sample of 57 quasars in the redshift
range 1.5<z<3.0- the epoch during which the comoving density of luminous AGN
peaks- to make a systematic comparison with an equivalent sample at high (z>4)
redshift. The target sensitivity of the survey (3sigma=10mJy at 850um) was
chosen to enable efficient identification of bright submm sources, suitable for
detailed follow-up. 9 targets are detected, with fluxes in the range 7-17mJy.
Although there is a suggestion of variation of submm detectability between z=2
and z=4, this is consistent with the K-correction of a characteristic
far-infrared spectrum. Additionally, the weighted mean fluxes of non-detections
at z=2 and z>4 are comparable.
