Over the past 20 years, few investment banks have run so far and so hard only to find themselves right back where they started. The Royal Bank of Scotland has become the corporate version of an endless Escher staircase.

The most recent restructuring in the markets division at RBS - in which the bank is stripping right back to its core fixed-income business - winds the clock back to the late 1990s. With a little more political pressure from the UK government, RBS may yet be forced to retreat further into the past and spin off arguably the best part of its business.