Britain's top five banks may be on track to axe up to 2,400 more branches, according to new research which says 12,000 jobs would be at risk as a result.
The report by banking and financial services analyst David Black, of DJB Research, and commissioned by the Nottingham Building Society, pointed to estimates suggesting that a network of just 600 branches could deliver "effective nationwide customer coverage".
"Looking at the number of branches the top five banks have today, I estimate that, if this strategy was adopted, some 2,400 branches could still be closed," Mr Black said.
That figure would represent a closure of around 25% of the existing bank branch network for Lloyds, RBS, NatWest, Barclays and HSBC.
Research from consumer group Which? shows that 670 branches have already been closed this year, with the figure for the whole of 2018 on track to eclipse last year's figure of 879 closures.
Earlier this year, Lloyds announced plans to shutter 49 branches across its Lloyds and Halifax brands between July and October this year, adding to 100 branch closures announced last year.
RBS also announced plans to close 162 branches across England and Wales, on top of 259 closures announced last autumn.
HSBC recently ruled out further closures, saying HSBC's network had already been reduced in recent years to the "optimal size".
"There is little doubt that more bank and building society branches will close - this is inevitable as the way people manage their money is changing," Mr Black said.
"However, the extent to which they are closing could be radically reduced if branches took on new services and approaches."
The report predicts that some existing branches could reduce in size, removing cashiers and adding coffee shops to boost footfall in locations that would start to resemble a "convenience supermarket-style" approach where customers serve themselves when paying in cheques or managing savings accounts.
David Marlow, chief executive of Nottingham Building Society, said branches that focus only on transactions have "limited value".
He pointed to his own bank, which he said has "reinvented" its proposition to offer services ranging from financial advice, whole of market mortgage comparison, savings accounts and estate agency services at select branches.
The move has boosted footfall by 10%, Mr Marlow said.
It has also doubled its branch network to 67 over the past five years.
The building society cited additional research showing that 53% of people keen to use branches would utilise branch-based savings accounts, while 32% would take advantage of independent financial advice, and 22% interested in mortgage services.
Meanwhile, 29% of people in the UK already expect the rate of branch closures to rise "dramatically" over the next three years, while around 49% predict at least a slight increase in the number of sites being shuttered.
Echoing concerns about dwindling services, one in four people believe they would suffer from "financial exclusion" if their local branch closed, resulting in restricted access to advice, services and financial products.
Around 40% of those who already claim to suffer from financial exclusion say a branch closure contributed to their circumstances.