NatWest payments glitch 'one week old', not days

RBS Group problems may last until Monday and are preventing some suppliers being paid. Branches to open this Sunday, says bank

The payments glitch that has affected the computer systems of NatWest, Ulster Bank and Royal Bank of Scotland (RBS) was caused by an RBS Group systems upgrade that went wrong and has been affecting some customers since Friday 15 June, Computing can reveal.

RBS Group owns NatWest, Ulster Bank and also Coutts & Co, and currently still owns insurance conglomerate Direct Line. Coutts & Co and Direct Line have told Computing that they have not been affected by the technical problems.

Some readers who have contacted Computing say that problems started a week ago, when they were unable to access their accounts online and were told that this was due to a technical glitch. One corporate customer of NatWest has told Computing that it has been unable to pay contractors this week via BACS.

The problems will last until at least Monday, RBS Group has announced, and could cost the bank millions of pounds in compensation, according to reports.

The glitch has affected 12 million RBS Group account holders, preventing them from accessing accounts online, withdrawing money at cash machines, making payments in shops or online, and transferring money to suppliers, staff and contractors.

NatWest announced today that 1,000 of its branches will open on Sunday from 9am to 12 noon.

The problem has caused mayhem in supermarkets, where customers have had their cards declined – despite having sufficient funds in their accounts to pay. In addition, some other customers have been plunged into the red as a result of the glitch, potentially incurring penalty charges with bounced direct debits, while house buyers have reportedly been unable to complete purchases.

Other people have been left stranded in the UK and abroad as a result of the problem.

A text message sent to customers this morning stated: "Due to systems issues, any money credited to your account overnight may not appear on your balance this morning. We are working to fix and apologise for the inconvenience". It also opened 1,000 branches until 7pm on Thursday evening and opened early on Friday to deal with customer complaints.

The bank said that the problem was caused by a software upgrade in the banks' payment system and that it has now been resolved. However, the backlog of payments will take up to a week to process, it added.

• RBS Group faces other problems: the state-backed bank's credit rating was downgraded by one point today by ratings agency Moody's, along with several other major banks.