  As part of a stellar population sampling program, a series of photometric
probes at various field sizes and depths have been obtained in a low extinction
window in the galactic anticentre direction. Very deep CCD frames probe the
most external parts of the disc, providing strong evidence that the galactic
density scale length for the old disc population is rather short (2.5 kpc) and
drops abruptly beyond 5.5-6 kpc. Deeper frames in the I band allow to estimate
photometric distances and confirm the position of the disc edge. A few stars
are found at larger distances. Their number is exactly what we expect if the
thick disc does not have any cutoff. We discuss the implications for the
formation and evolution of the disc, for the star formation threshold, and for
the origin of the thick disc population.
