  We report on the computation of a class of integrals that appear when
integrating the so-called iterated singly-unresolved approximate cross section
of the NNLO subtraction scheme of [1-4], over the factorised phase space of
unresolved partons. The integrated approximate cross section itself can be
written as the product of an insertion operator (in colour space) times the
Born cross section. We give selected results for the insertion operator for
processes with two and three hard partons in the final state.
