In the event of a breach of security, centralised databases can lose colossal amounts of personal information. Apart from the security measures already mentioned (encryption, fraud monitoring, firewalls, PINs etc.) it may be worth avoiding centralising data. Instead each county could run its own system at very little extra cost.
It may even be possible to put the servers, which take up little space, in already secure buildings (e.g. police stations?) so that costs don't escalate.