%0 Journal Article %T Vacuum Polarisation and the Black Hole Singularity %A W. G. Anderson %A P. R. Brady %A R. Camporesi %J Physics %D 1992 %I arXiv %R 10.1088/0264-9381/10/3/009 %X In order to investigate the effects of vacuum polarisation on mass inflation singularities, we study a simple toy model of a charged black hole with cross flowing radial null dust which is homogeneous in the black hole interior. In the region $r^2 \ll e^2$ we find an approximate analytic solution to the classical field equations. The renormalized stress-energy tensor is evaluated on this background and we find the vacuum polarisation backreaction corrections to the mass function $m(r)$. Asymptotic analysis of the semiclassical mass function shows that the mass inflation singularity is much stronger in the presence of vacuum polarisation than in the classical case. %U http://arxiv.org/abs/gr-qc/9211016v1