Not only banks, but other financial services companies were also given advice by the Bank of England and the Financial Conduct Authority to report back by October 5 on their exposure to risks and how they would respond to outages.

The vulnerability of the banking system to technology failures has been highlighted recently by the inability of customers of bank TSB to access their online accounts and problems at payments company Visa.

Moreover, FIs such as banks and insurers will have to demonstrate to regulators that they have a plan for when crucial systems such as online banking or payment services are disrupted, either by systems failure or deliberate attack. If companies fail to demonstrate adequate back-up plans, regulators could require them to take actions such as bolstering capital levels or investing in making their systems more resilient.

The regulators suggested two days as an acceptable limit for disruption to a business service in one scenario spelt out in a consultation paper published on Thursday.

The decision comes after some customers of TSB bank were still unable to access online banking services over a month after its first outage in April 2018, which followed a botched systems upgrade.