  We compute the exponential disc scalelength for 686 disc galaxies with
spectroscopic redshifts out to redshift 5.8 based on Hubble Space Telescope
archival data. We compare the results with our previous measurements based on
30000 nearby galaxies from the Sloan Digital Sky Survey. Our results confirm
the presence of a dominating exponential component in galaxies out to this
redshift. At the highest redshifts, the disc scalelength for the brightest
galaxies with absolute magnitude between -24 and -22 is up to a factor 8
smaller compared to that in the local Universe. This observed scalelength
decrease is significantly greater than the value predicted by a cosmological
picture in which baryonic disc scalelength scales with the virial radius of the
dark matter halo.
