Seven million NatWest, Royal Bank of Scotland (RBS) and Ulster Bank customers are being told they will no longer receive monthly paper bank account statements unless they opt back into the system.
The three banks are all part of the same group, which has started writing to customers to tell them their statements will only be sent in the post every three months.
People who want to continue to have letters delivered on a monthly basis will need to get in touch with their bank. A spokeswoman for RBS Group said that around seven million current account customers who receive paper statements will be affected.
She said the move had not been prompted by cost-cutting but it was a response to customer feedback and requests, as people increasingly manage their finances online. The group also highlighted the benefits to the environment brought by the changes.
RBS Group was hit by a massive IT meltdown over the summer, which caused chaos for customers for weeks, with Ulster Bank customers suffering for a particularly lengthy period.
The group has promised that no one will be left out of pocket as a result of the hitches. RBS set aside £125 million for dealing with the fiasco in its half-year results but has warned the costs could escalate.
NatWest and RBS customers have already started receiving letters about the changes to their statements and Ulster Bank customers will be written to in the new year. Customers are being given 60 days to opt out of the change-over but following this period they will still be able to change the frequency of their statements.
A statement from the group said: "Increasing numbers of our customers are choosing to do their banking online and many have asked us to reduce the amount of paper statements we send out.
"In response to that we're in the process of writing to our current account customers to tell them that their paper statements will soon be issued every three months. The change is not compulsory and we will continue to send monthly paper statements to customers who ask us to."
Customers who want to continue receiving monthly statements can make a request in branch, on the phone or online. Those who go on to receive quarterly paper statements can continue to keep track of their accounts by requesting free mobile text and email alerts.