Marks & Spencer is to offer current accounts from this autumn after announcing plans to open 50 bank branches in the next two years.
The first outlet at M&S's Marble Arch store in London is due to open next month and will mirror shop opening hours, meaning seven days a week banking.
The company, which expects to create 500 UK jobs from the roll-out of the M&S Bank business, said mortgages will be offered at a later date.
It already provides credit cards, loans and savings to more than three million customers under M&S Money, which is run as a joint venture with HSBC.
M&S chief executive Marc Bolland said the chain will look to build on its reputation as one of the high street's most trusted brands.
He said: "This bank will be built on M&S values, putting the customer at the heart of the proposition and delivering the exceptional service that sets us apart from the competition."
HSBC described the venture as its most "significant innovation" in UK retail banking since it launched First Direct more than 22 years ago.
The launch of a new player in the lending market comes as mainstream banks battle to win back the confidence of customers.
David Black, a banking specialist at financial research company Defaqto, said the retailer's venture "provides another option" for customers at a time when supermarket giant Tesco is also expanding its financial products.
He said: "It's pretty good news, particularly to have 50 planned banks open on Sundays."