  We derive a new metallicity distribution of G dwarfs in the solar
neighbourhood, using uvby photometry and up-to-date parallaxes. Our
distribution comprises 287 G dwarfs within 25 pc from the Sun, and differs
considerably from the classic solar neighbourhood distribution of Pagel &
Patchett and Pagel by having a prominent single peak around [Fe/H] = -0.20 dex.
The raw data are corrected for observational errors and cosmic scatter assuming
a deviation of 0.1. In order to obtain the true abundance distribution, we use
the correction factors given by Sommer-Larsen, which take into account the
stellar scale heights. The distribution confirms the G dwarf problem, that is,
the paucity of metal-poor stars relative to the predictions of the simple model
of chemical evolution. Another feature of this distribution, which was already
apparent in previous ones, is the small number of metal-rich stars again in
comparison with the simple model. Our results indicate that it is very
difficult to fit the simple model to this distribution, even with the
definition of an `effective yield'. A comparison with several models from the
literature is made. We find that models with infall are the most appropriate to
explain the new metallicity distribution. We also show that the metallicity
distribution is compatible with a major era of star formation occurring 5 to 8
Gyr ago, similar to results found by several authors.
