  We measure the volume luminosity density and surface luminosity density
generated by the Galactic disc, using accurate data on the local luminosity
function and the disc's vertical structure. From the well measured volume mass
density and surface mass density, we derive local volume and surface
mass-to-light ratios for the Galactic disc, in the bands B, V and I. We obtain
mass-to-light ratios for the local column of stellar matter of (M/L)_B = 1.4
+/- 0.2, (M/L)_V = 1.5 +/- 0.2 and (M/L)_I = 1.2 +/- 0.2. The dominant
contributors to the surface luminosity in these bands are main sequence
turn-off stars and giants. Our results on the colours and mass-to-light ratios
for the ``Solar cylinder'' well agree with population synthesis predictions
using Initial Mass Functions typical of the Solar Neighbourhood. Finally we
infer the global luminosity of the Milky Way, which appears to be
under-luminous by about 1-sigma with respect to the main locus of the
Tully-Fisher relation, as observed for external galaxies.
