In the winter after the fall of the Berlin Wall in 1989, the 38-year old KGB officer Vladimir Putin returned almost penniless from Dresden to his native city of St Petersburg in the collapsing Soviet Union. He had a 20-year-old washing machine and savings from his monthly salary of $270.

Within a decade he had become a millionaire; within 20 years he had turned himself by some accounts into one of the wealthiest people in the world. This was not a conventional entrepreneurial rags-to-riches progression. Mr Putin used his power to make connections with the business world, help them to prosper and shield them from bureaucracy.

As Mr Putin’s friends grew rich, so, says the US, — despite his denials — did he. US investigators