The authors have measured the 7Li abundance in G 64-12 an extremely metal-deficient dwarf [Fe/H] = -3.5 (Carney and Peterson, 1981) with effective temperature Teff = 6350K, and a very high velocity Vrad = 439 km/s. The result is log N(7Li) = 2.23 (±0.20), where log N(H) = 12. This star has a considerably lower metallicity than previous population II dwarfs with measured 7Li. The proximity of this 7Li abundance to those previously measured in halo dwarfs together with its relatively high Teff lends added support to the view that lithium abundance of just over 2 represents an essentially undepleted primordial value. This taken together with recent estimates of primordially produced 4He places tight constraints on the universal baryon to photon ratio.