British bank Barclays Plc said it shut down its Internet banking service yesterday, after a glitch in new software allowed some users to see other customers' accounts.

The security breach was discovered after the bank launched an upgraded Internet service on Saturday night.

Barclays said four users contacted it yesterday to say they were shown other customers' balance statements when they logged on, but the bank insisted they would not have been able to place transactions on those accounts.

Barclays, which has 85,000 online customers, said it had shut down the service and would reinstall the original software. "Barclays views this compromise in security as unacceptable," it said in a statement.