  We study central Z-boson production accompanied by rapidity gaps on either
side as a way to gauge Higgs weak boson fusion production at the LHC. We
analyse the possible backgrounds for the bb-decay mode and show that these can
be substantially reduced. Special attention is paid to the evaluation of the
gap survival factor, which is the major source of theoretical uncertainty in
the rate of H, Z and W central production events with rapidity gaps.
