M&S Bank is a clever move – but they need to keep the lingerie lovers too

Marks & Spencer is to shake up the High Street with the launch of its own bank. The retail giant will offer current accounts and home loans to its army of loyal customers.

The first branch is expected to open next month inside M&S's flagship central London store near Marble Arch, with 20 more in the pipeline. And in a further challenge to Britain's financial services sector, the new bank is also set to open on Sundays.

David Black, banking specialist at financial data group Defaqto, said: 'This could be a real shake-up on the High Street. M&S is a brand very well-trusted by lots of faithful customers and the retailer could attract a lot of people desperate to escape high street banks who have had a really bad reputation for customer service over the past few years.'

M&S already offers financial services such as foreign currency exchange in some stores, credit cards, insurance and personal loans.

It already has three million credit card customers as well as hundreds of thousands who have bought its life and travel insurance and will be able to offer a current account and mortgage because its parent company HSBC already has a banking license.

M&S is also going to have to manage its customer service carefully. As one mortgage broker says, "I want to be offered the same level of service for mortgage advice as I do for buying underwear or a suit." Or, as another put it: "You're only as good as your worst person in your branch."