Britain's recurring 19th-century banking panics (1819-1857) stemmed from Parliament pressuring the Bank of England to provide an implicit put option on the London bills market—a quid pro quo for its privileges, directly analogous to Fannie Mae/Freddie Mac—and the crises ended only after the Bank publicly renounced this put in 1858 and credibly enforced it by letting Overend Gurney fail in 1866 despite having bailed it out in 1857.