Immunisation is one of most evidence-based activities of the NHS, and much of its success owes to the sensible use of information systems which both run the programme and at the same time evaluate its implementation. The recovery of the national programme from the whooping cough vaccine scare of the 1970’s (when coverage fell to ~30%) owed a lot to improvements in co-ordination of the programme including the use of information technology which was rolled out nationally in the 1980’s. The much smaller fall in coverage which occurred following the MMR and autism scare in the late 1990's is at least in part a tribute to these better systems. It is therefore a retrograde step that new software chosen by the local providers as part of Connecting for Health has had less functionality than the systems it is replacing. This has consequences for general practitioners, practice nurses, Primary Care Trusts, public health departments and for parents and children. The immunisation programme is something which everyone takes for granted until things go wrong. Lessons from two decades of good practice should be taking the Immunisation programme in London forwards; ignoring these lessons has taken it backwards.