Tesco Bank has delayed a major system migration programme. This has followed severe problems the bank experience in June that locked out customers from their accounts for three days.

The issues were the result of a summer switch over from RBS to Tesco-run technology.

Clarke, once Tesco’s IT director, said the company was “slowing down” the migration in order to ensure the changeover goes “without a hitch”. The problems the bank had experienced were “not good”, he said.