RBS has incurred costs totaling £175 million as a result of the botched upgrade that disrupted IT systems for nearly a week this summer.

In its financial report published today, the bank revealed that set aside a further £50 million to compensate customers and cover other charges relating to the incident in the most recent quarter. The costs came primarily from RBS subsidiary, where outages were especially prolonged.

This brings the grand total up to £175 million.

The £50 million charge is just the latest in a string of indictments for RBS’ legacy IT infrastructure.

Earlier this month, Spanish banking giant Santander pulled out a £1.7 billion deal to buy over 300 RBS branches in the UK. The deal was struck in 2010, but had been much delayed. An Accenture reporting into the causes of the delay found that the complexity of RBS’ technology platform was partly to blame.

Last week, the Telegraph reported that RBS plans to invest £80 million in upgrading its IT infrastructure. RBS did not comment at the time, and there is no confirmation in its financial report.