Every chief information officer would like to start with a clean sheet of paper on which to design a system in which every element worked seamlessly with every other. But enterprise IT systems today – the “back office” – are hostages to their history.

For most companies the IT script has been written and rewritten over the years and decorated with blots and smudges and crossings-out. The multiplicity of servers in many organisations, each running incompatible software, is mute testimony to that fact.