  We present JHKL' photometry of a complete sample of steep-spectrum radio-loud
quasars from the revised 3CR catalogue in the redshift range 0.65 < z < 1.20.
After correcting for contributions from emission lines and the host galaxies,
we investigate their spectral energy distributions (SEDs) around 1 micron.
About 75% of the quasars are tightly grouped in the plane of optical spectral
index, alpha_lo, versus near-infrared spectral index, alpha_hi, with the median
value of alpha_lo close to the canonical value, and the median alpha_hi
slightly flatter. We conclude that the fraction of moderately-obscured, red
quasars decreases with increasing radio power, in accordance with the `receding
torus' model which can also explain the relatively flat median near-infrared
spectra of the 3CR quasars. Two of the red quasars have inverted infrared
spectral indices, and we suggest that their unusual SEDs might result from a
combination of dust-scattered and transmitted quasar light.
