Immigration Service head Mary Anne Thompson has resigned. Good. What she was accused of doing - arranging visas and residency for relatives in contravention of normal immigration guidelines - undermined both our immigration policy and the entire public service. Such corrupt behaviour cannot be tolerated, and it is good that she was forced out. At the same time, I'm concerned that this will be used as an excuse to bury the SSC investigation, or put it on the back burner, which would be a mistake. We've had a serious incident of self-serving behaviour in our normally professional public service. We need to know how it happened, so as to prevent it from happening again in the future.