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 to by the
uncertainties on neutrino flux at the source. A reduction of this
uncertainty 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
$\bar{\nu}_e$) 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. We
present the Project, the first experimental results on ultra-compact
calorimeters that can embedded in the instrumented decay tunnel and
the advances on the simulation of the beam-line. A rich program of
detector R&D and accelerator-related activities are planned in
2016-2021.