The Royal Bank of Scotland has revealed that it will compensate customers who were affected by the mass outage to its online and phone banking services which has potentially left millions of people unable to purchase goods or receive payments.

Echoing the debacle in 2012, RBS said banking services are "coming back online" and will compensate those who are "out of pocket".

"If customers have been left out of pocket as a result of these system problems, we will put this right," said a RBS spokesperson.

"If any customer is unable to resolve an issue caused by the disruption, they should get in touch with our call centres or come into a branch in the morning where our staff will be ready to help."

RBS received a taxpayer funded £45bn (€54bn, $73bn) bailout in 2008 and was eventually 81% owned by the government.

Will Customers Be Able to Receive Payments?

Since 6pm GMT customers told IBTimes UK that said they are unable to access any online services while a number say they are not even able to pay for goods by card after being declined.

While some customers reported that they have been able to pay for goods via PayPal from around 9.45am GMT, a number of people have since contacted IBTimes UK to say they are still unable to do so and are waiting to receive benefit payments.

"I am now able to login and see my accounts [but] I am unable to make any form of payment or withdrawal," said one customer to IBTimes UK.

"I am still unable to make any payments of any form. I am unable to even transfer money from my account elsewhere into my RBS account - I am told by Halifax customer services all payment services are down at RBS. It must be bad if they can't receive money as well. "

Another said, "I have been trying since 2am to access my online banking, as need to pay bills and do shopping , but am still unable to do so."

Another customer told IBTimes UK that they have not received welfare payments.

"We have been paid child benefit into our accounts on a Tuesday for years, however it is not showing as paid today," they said.

A number of those in more vulnerable positions highlighted to IBTimes UK how not being able to make purchases or receive payments will hit them hard even in the short term.

"I am looking after my mother who is terminally ill. I have no petrol in my car and no means of buying essential items of shopping. This is a disgrace. I want to know how this will be rectified and when," said a customer.

History of Problems

RBS and one of its retail subsidiaries Natwest are no strangers to technical faults for their consumer banking services.

In August 2012, RBS revealed that it had put aside £125m to compensate thousands of customers affected by a two-week computer breakdown, which led to millions of customers being stranded and unable to pay outgoing bills.

In April this year, Britain's financial watchdog said it will investigate RBS over its 2012 computer failure that left millions of customers unable to access their accounts.

The Financial Conduct Authority launched an enforcement proceeding into the IT failures which occurred in June and July 2012.

"The FCA will reach its conclusions in due course and will decide whether or not enforcement action should follow that investigation," the statement said. RBS had around 17m customers at the time of the system failure but has never confirmed how many were affected by the fault.

It set aside £125m in August last year to compensate affected customers.

The now-ousted RBS CEO Stephen Hester admitted the bank had "let down" customers because of the system-wide failure and apologised to customers and shareholders.