  In the context of a subtraction method for jet cross sections at NNLO
accuracy in the strong coupling, we perform the integration over the
two-particle factorised phase space of the collinear-type contributions to the
doubly unresolved counterterms. We present the final result as a convolution in
colour space of the Born cross section and of an insertion operator, which is
written in terms of master integrals that we expand in the dimensional
regularisation parameter.
