UK Internet bank Egg has been unable to offer an online banking service to its customers since the beginning of the week, having suffered problems with its back-end infrastructure. The bank, launched by Prudential, recently upgraded its Internet site, but a spokeswoman says the current problems have nothing to do with the upgrade process. She says that the company is desperately investigating the cause of the disruption to the services section of its site. "We have all our experts working on it at the moment. It's a back-end thing." Although customers of the Internet bank cannot currently view account transactions and balances over the Internet, the spokeswoman says that customers have not been left in a tight spot. "We have a phone service, so none of our customers are disadvantaged." The spokeswoman says that Egg does not know when the problem will be resolved. A poll carried out in July 2000 by Internet ratings service Net Value showed that Egg was the UK's most popular online banking service. The bank announced in December that it has 1.33 million users and said it hoped to break even in Q4. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.