Major banks ready their own mobile payment apps

That changed with the launch of Apple Pay on October 20. A million cards were activated in the first three days of use and early adopters have praised its ease of use: users just need to hold their thumb over the iPhone 6 fingerprint reader and bring the device near a terminal for payment to be made.

As a result, competitors are planning their attack. Next year CurrentC, backed by some of the biggest retailers in the U.S., will launch and companies like PayPal are also hoping to expand their footprint in stores.

But an app from a bank might have an edge because it removes a potential hurdle to adoption: unease among consumers that at a third-party is getting access to details of purchases they make.

Apple has stressed that it doesn't see any of the purchases made by its users but Google's system is set up so that all payments run through the company's servers -- giving the company an additional layer of information into the lives of its users.

A bank already has access to this information because of its nature and is presumably trusted by its customers. If a customer has a banking app on their phone, it would suggest they also have faith in the bank's online security system.