Cyber security is the greatest risk faced by financial institutions today, a risk they have understood and managed for decades longer than is commonly understood. Ever since the major London banks purchased their first computers in the early 1960s, they have had to balance their dependence on those machines with the need to secure their operations and retain the trust of their customers.

Technological change in the second half of the 20th century prompted British banks to reevaluate their function as trusted protectors of wealth. In the City of London, the capital’s oldest area...

Cyber security is the greatest risk faced by financial institutions today, a risk they have understood and managed for decades longer than is commonly understood. Ever since the major London banks purchased their first computers in the early 1960s, they have had to balance their dependence on those machines with the need to secure their operations and retain the trust of their customers.

Technological change in the second half of the 20th century prompted British banks to reevaluate their function as trusted protectors of wealth. In the City of London, the capital’s oldest area...