Currently a Brit like me has a unique identity on each of a number of large IT systems - DVLC, NI, passport control, customs and revenue etc. These major systems can neither speak to one other, nor be subdivided, because the limits of my secure identity on the system, and the processing of my information within the system, must share the same boundaries. You can't split National Insurance into sub-programmes because I don't have a transferable secure identity external to and independent of the NI system, so any processing activity which utilises my NI-identity has to occur within the single mega-programme within which alone that identity is meaningful.
This means that only three or four massive organisations like Capita can bid for the big government IT projects, and it makes them lazy, complacent and expensive IMHO. The Conservatives (for example) have said that 'we will open up government contracts to SMEs and open source by breaking up large ICT projects into smaller components'. But they have also said they will work against establishing a single transferable identity system.
I think these aims, both of which are good in isolation, are incompatible. Criticism of ID has mostly been taken forward by the most well educated and intelligent of pro-Tory voters, so I have been very disappointed that the big advantage of secure transferable ID - that it allows fragmentation of monolithic IT projects as demanded by the same people - has not been addressed. But point me to it if I'm wrong, I'd be really interested if this circle has been squared. (ETA - I'm not being sarcastic, if there are solutions I don't understand then they should be explained to people like me who are uninformed)