  We design a Hybrid High-Order (HHO) scheme for the Poisson problem that is
fully robust on polytopal meshes in the presence of small edges/faces. We state
general assumptions on the stabilisation terms involved in the scheme, under
which optimal error estimates (in discrete and continuous energy norms, as well
as $L^2$-norm) are established with multiplicative constants that do not depend
on the maximum number of faces in each element, or the relative size between an
element and its faces. We illustrate the error estimates through numerical
simulations in 2D and 3D on meshes designed by agglomeration techniques (such
meshes naturally have elements with a very large numbers of faces, and very
small faces).
