  The challenges of precision neutrino physics require measurements of absolute
neutrino cross sections at the GeV scale with exquisite (1%) precision. This
precision is presently limited by the uncertainties on neutrino flux at the
source; their reduction by one order of magnitude can be achieved monitoring
the positron production in the decay tunnel originating from the $K_{e3}$
decays of charged kaons in a sign and momentum selected narrow band beam. This
novel technique enables the measurement of the most relevant cross sections for
CP violation ($\nu_e$ and $\overline{\nu}_e$) with a precision of 1% and
requires a special instrumented beam-line. Such non-conventional beam-line will
be developed in the framework of the ENUBET Horizon-2020 Consolidator Grant,
recently approved by the European Research Council. The project, the first
experimental results on ultra-compact calorimeters that can be embedded in the
instrumented decay tunnel and the advances on the simulation of the beamline
are presented. We also discuss the detector and accelerator activities that are
planned in 2016-2021.
