A number of Tesco Bank customers were unable to access their accounts while the bank underwent system migration, it has been revealed.

Tesco Bank was migrating savings and loans accounts from RBS’s systems over the weekend to its Fiserv Signature bank platform, when the problems occurred.

The bank initially launched as a joint venture with RBS. Last week, Tesco said its banking business was making “good progress” and that it was in the final stages of the transition to its own systems and infrastructure.

It also said that its savings and loan platforms had started operating for new customers, and that it would be migrating existing accounts “imminently”.

According to the BBC, the issue has now been fixed.

“For a brief period some customers were unfortunately unable to access their accounts. We apologise for this, but can reassure them that the process is now complete and all customers can access their accounts online as normal,” a Tesco spokesperson told the broadcaster.

Tesco Bank launched in 1997, became independent from RBS in 2008, and has 6.5 million customers. It offers savings accounts, loans and credit cards, and insurance for cars, homes and travel. It operates an in-store, phone and online business model.