Royal Bank of Scotland was fined £56 million yesterday following June 2012 IT meltdowns which prevented millions of customers from accessing their accounts.

The issues stemmed from a failed upgrade to the software that processed updates to customers' accounts overnight.

Over the course of several weeks, some customers could not use online banking facilities or obtain accurate account balances from cash machines.

They were also unable to make mortgage payments on time and some customers were left stranded abroad.

The firm also applied incorrect credit and debit interest to customers' accounts and produced inaccurate bank statements.

RBS has already paid more than £70m to customers as a result of the crash, which it blamed on "unacceptable weaknesses" in its systems.

The Financial Conduct Authority fined RBS £42m, while the Bank of England's Prudential Regulation Authority issued a separate penalty of £14m.