Lloyds Bank has announced plans to shrink hundreds of its branches in size, in some cases boarding up the old counter sections.
The new “micro branches” will be staffed by just two people, who will help customers to use machines, including pay-in devices.
Some of those being converted will be Halifax and Bank of Scotland branches.
Lloyds said the reason was “a profound change in customer behaviour”, which has seen more transactions move online.
It has already announced plans to close 400 of its branches around the UK, with 9,000 job losses.
The micro format, modelled on an existing branch in Paternoster Square in the City of London, will use as little as 1,000 square feet of space.
“We have a lot of branches that used to have a lot of footfall, and therefore feel quite empty and intimidating for customers,” said Jakob Pfaudler, Lloyds’ chief operating officer for retail.
“So when there’s too much space we may board up places in existing branches.”
There will be no counters in the new micro branches. Instead the staff will be mobile, and will carry tablet computers to help customers.
Other banks have already made similar changes.
There will be video links for customers to talk to mortgage advisers, but for complex transactions they will have to visit a bigger branch.
As part of the changes Lloyds will also open up to 20 much larger banking centres, which will have a full range of facilities, including sections for entrepreneurs.
“Think Apple store, as opposed to bank branches,” said Mr Pfaudler.
The first, a Lloyds branch, will open in the centre of Manchester this year. That will be followed by a flagship Halifax branch in central London.
Medium-sized existing branches will be re-designated as “community” branches – in rural areas – or “anchor” branches in towns and cities.
The bank is also introducing three more mobile vans over the next few weeks, in South Wales, Devon and Gloucestershire.
By the end of this year Lloyds will be left with about 1,950 branches around the UK, meaning it will still have the largest network of any High Street bank.
Research by Which? suggested that in total more than a thousand branches closed in the UK in the two years to December 2016.
Last month, RBS and NatWest announced that 158 further branches would close, while HSBC is planning to shut 62 branches this year.