  We determine the radial abundance gradient of helium in the disc of the
Galaxy from published spectra of 19 $\text{H}\thinspace \text{II}$ regions and
ring nebulae surrounding massive O stars. We revise the Galactocentric
distances of the objects considering {\it Gaia} DR2 parallaxes and determine
the physical conditions and the ionic abundance of He$^{+}$ in a homogeneous
way, using between 3 and 10 $\text{He}\thinspace \text{I}$ recombination lines
in each object. We estimate the total He abundance of the nebulae and its
radial abundance gradient using four different ICF(He) schemes. The slope of
the gradient is always negative and weakly dependent on the ICF(He) scheme,
especially when only the objects with log($\eta$) $<$ 0.9 are considered. The
slope values go from $-$0.0078 to $-$0.0044 dex kpc$^{-1}$, consistent with the
predictions of chemical evolution models of the Milky Way and chemodynamical
simulations of disc galaxies. Finally, we estimate the abundance deviations of
He, O and N in a sample of ring nebulae around Galactic WR stars, finding a
quite similar He overabundance of about +0.24 $\pm$ 0.11 dex in three stellar
ejecta ring nebulae.
