Workers at Lloyds TSB call centres have been told they must no longer read from scripts when talking to customers because it makes them angry.
Reading from a script can lead to phone rage
Researchers found that 90% of people got annoyed when they were talking to call centre workers who were obviously reading from a script.
Most customers said they thought this led to staff failing to listen or answer questions properly.
Scripted conversations were impersonal and often went on too long, they said.
Call centre staff agreed that reading from scripts slowed down the process and 86% of them backed scrapping them.
Lloyds TSB said it would replace most of the scripts with templates designed to guide staff through the main points they need when chatting to customers.
"But where sales are concerned, for example buying insurance or taking a loan, we have to make customers aware of compliance procedures and FSA regulations," said spokesman Emile Abu-Shakra.
"So it is in our interests and theirs to keep those scripts the same."
Other banks already follow different procedures.
Barclays, for example, said their call centre staff did not follow scripts, although their computer database would throw up questions that needed answering depending on different customer circumstances.
Meanwhile, First Direct, part of the HSBC Group, said it only scripted its security clearance questions.
Lloyds TSB handles about 70 million calls a year, employing 4,000 people in calls centres around the UK and in India.
"By ditching the scripts in our call centres, we are giving staff the freedom to treat every customer as an individual and build a much closer rapport with them," said Martin Dodd, telephony operations director at the banking group.