We will present the pilot results of the Lancaster deep CaHK narrow-band surveys for metal-poor stars in the halo of the Milky Way. We explore deep NB392 and CaHK data obtained with the INT and CFHT over several extra-galactic fields and combine them with the full deep multi-wavelength data to identify extremely metal poor stars down to [Fe/H]~-5. Our survey is able to identify very metal poor F, G and K type stars all the way to the edges of the galactic halo in multiple sight-lines for the very first time. We will present the best candidates for extremely metal poor stars, the number density distribution in terms of temperatures and metallicities in the halo, and also the metallicity distribution and gradients that we recover. Follow-up observations will allow to confirm and fully establish the very low metallicity of these halo stars, along with potentially confirming the best candidates as low metallicity record breakers.