Marks & Spencer is to shake up the financial services industry with the launch of its own bank.

The first branch will open next month in the retailer’s flagship Marble Arch store and another 20 are already planned. Services will include mortgages.

All bank branches will be in shops and will open the same hours, including Saturdays and Sundays.

Marks & Spencer aims to make the most of the strength of its brand and hugely trusted status in an industry that has suffered from a poor image among consumers, it is understood.

The retailer already has a strongly performing financial services arm, M&S Money, which made a profit last year of £50m. It is a top-10 credit card provider with more than 3 millon customers, and is the second-biggest travel money retailer in the UK. M&S Money operates as a joint venture between HSBC and M&S and has its own board.

Retailers are increasingly pushing into services such as banking as a complement to their core operations.

The Co-operative Group has a well established banking division. Tesco also runs a bank but its much-vaunted launch of current accounts has been delayed until next year. The giant grocer had originally hoped to introduce the service this year but was hit by technology problems which denied savings accounts holders access to their online accounts.

No comment was available from Marks & Spencer.