Nowadays the leading contender to understand the initial conditions of the Big Bang is inflation, which predicts the existence of a primordial background of gravitational waves that must have left its imprint in the CMB polarization: the so-called ​ B-modes. The main difficulty in measuring the ​ B-modes comes not just from its sheer faintness but from the fact that many other objects in the universe also emit polarized microwaves.

The European Low Frequency Survey (ELFS) is a project that will allow the detection of the ​ B-modes by measuring the Galactic and extra-Galactic foregrounds in the 5 - 120 GHz frequency window, and with at least 30 arcmin resolution at 5 GHz,
which is currently essentially unexplored at the required precision level. This characterizes ELFS with a strong complementarity and combination potential with other  probes.

In this talk I will briefly review the scientific motivation for ELFS, its instrumental characteristics and the team plans towards the constitution of a scientific consortium.