Police IT is something I've worked in, in the past, but centrally rather than Force-based. Some forces do it well, others less so. I think it comes back to the big issue of having 43 forces in England and Wales, rather than one like Scotland or NI. Having said that, data control is often a weak point due to lack of understanding. The NI data loss (the spreadsheet released to the web) was almost certainly a case of someone using Excel filters to cut down the data visible, not realising that you could turn off the filters and see everything. Losing a laptop, deliberately or accidentally, does happen - I had two stolen from my car once, both with secure data on them, but they were so locked down they would have self-destructed if someone tried very hard to break in. I don't know details of the South Yorks instance yet.
NHS IT is a whole other ballgame - lack of systems integration is unforgivable, considering how relatively straightforward it can be. But remember the big project to join everything up back in the 2005 or thereabouts period? I think Andersen's were running it, and they just screwed it up big time. I've run pan-European integration projects more complex than that, which did take a long time, but were achieved successfully through good collaboration. I suspect the issue in the NHS is based on local managers not wanting to lose their positions of influence to a centrally-managed entity (of which there are many in the NHS).