Until, of course, in 2013 the Silk Road was shut down by FBI agents and Mr Ulbricht, then 29 years old, was arrested in the science-fiction section of a San Francisco public library. In 2015, after a four-week trial,

Ulbricht’s conviction has been wiped out, but his 144,000 Bitcoins are long gone.

Law enforcement said Ulbricht created the “most sophisticated and extensive criminal marketplace” on the internet.