European banks are becoming uncomfortably familiar with the American legal process. HSBC, Standard Chartered and RBS have all entered into deferred prosecution agreements with US watchdogs in recent months, admitting criminal liability for activities relating to money laundering, trade sanctions breaches and Libor-rigging.

Legal experts say US authorities are becoming increasingly willing to intervene in cases of financial wrongdoing with only tenuous links to the American market should foreign prosecutors be unable, or unwilling, to do so themselves.