We have used accurate, spectroscopically determined abundances for G and K dwarfs of Morell, Kallander & Butcher and Morell to derive a photometric abundance index for G and K dwarfs. Broad-band Cousins R - I photometry is used to estimate effective temperature and the Geneva b(1) colour to estimate line blanketing in the blue and hence abundance. Abundances can be derived in the range -2.0 <[Fe/H] < 0.5 for G0 to K3 dwarfs, with a scatter in [Fe/H] of 0.2 dex. We apply the method to a sample of Gliese catalogue G and K dwarfs, and examine the metallicity and kinematic properties of the stars. The stars show the well-established observational features of the disc, thick disc and halo in the solar neighbourhood. We find that the distribution of local K dwarf metallicity is quite similar to that of local G dwarfs, indicating that there is a 'K dwarf' as well as a G dwarf problem.