  We present a compact analytic expression for the leading colour two-loop
five-gluon amplitude in Yang-Mills theory with a single negative helicity and
four positive helicities. The analytic result is reconstructed from numerical
evaluations over finite fields. The numerical method combines integrand
reduction, integration-by-parts identities and Laurent expansion into a basis
of pentagon functions to compute the coefficients directly from six-dimensional
generalised unitarity cuts.
