The west used to worry about an over-mighty Russia. A Russia in decline is the more threatening proposition. Events in a London courtroom offer an uncomfortable reminder that this is where things are heading under Vladimir Putin.

Residents of Britain’s capital have a ringside seat at an extraordinary legal battle between two of Russia’s most famous, or, if you prefer, infamous oligarchs. It is a case destined to keep the city’s expensive lawyers in their silk-threaded suits for some considerable time.

The showdown between Boris Berezovsky and Roman Abramovich has been billed as a falling out among the oligarchs who grabbed a large slice of Russia’s resource wealth during the wild, post-Soviet 1990s. It’s certainly that. The more interesting dimension, though, is the window it opens on a Russia still trapped in the past.