  We present predictions, derived from the EAGLE LCDM cosmological
hydrodynamical simulations, for the abundance and properties of galaxies
expected to be detected at high redshift by the James Webb Space Telescope
(JWST). We consider the galaxy population as a whole and focus on the
sub-population of progenitors of Milky Way (MW) analogues, defined to be
galaxies with accretion histories similar to the MW's, that is, galaxies that
underwent a merger resembling the Gaia-Enceladus-Sausage (GES) event and that
contain an analogue of the Large Magellanic Cloud (LMC) satellite today. We
derive the luminosity function of all EAGLE galaxies in JWST NIRCam passbands,
in the redshift range z=2-8, taking into account dust obscuration and different
exposure times. For an exposure time of $T=10^5$s, average MW progenitors are
observable as far back as z~6 in most bands, and this changes to z~5 and z~4
for the GES and LMC progenitors, respectively. The progenitors of GES and LMC
analogues are, on average, ~2 and ~1 mag fainter than the MW progenitors at
most redshifts. They lie, on average, within ~60 and ~30 arcsec, respectively,
of their future MW host at all times, and thus will appear within the
field-of-view of JWST NIRCam. We conclude that galaxies resembling the main
progenitor of the MW and its major accreted components should be observable
with JWST beyond redshift 2, providing a new and unique window in studying the
formation history of our own galaxy.
