British Telecom faced an embarrassing setback to its mobile internet strategy when it said it did not know when its Genie portal would be fully operational, after more than a week of problems.

Britain's leading multi-platform portal has been completely or partly out of action since October 11, when an upgrade scheduled to take 12 hours ran into problems.

The failure could jeopardise BT Cellnet's lead over rival mobile operators, which view portals running on both desktop computers and cell phones as potential money spinners.

Genie users were unable to access the desktop version of the site at all until the weekend, since when it has remained intermittently unavailable.

One of the site's services, forwarding emails to mobile phones in the form of text messages, is still not working. A Genie spokesman claimed the site was fully operational, but an email received minutes later from Genie's customer care desk said it was still experiencing unexpected technical difficulties.

"This means it is taking longer than originally planned for the site to be fully operational. Although we do not have a time scale for a fix at the moment, we are told that the site will be running as soon as possible," the email said.

The problems were caused by difficulties in transferring databases to the upgraded site, Genie said last week.

Genie has been a rare internet success story for BT, attracting 1m users.

"I don't think they will lose large amounts of customers but their reputation will be tarnished as a result," said Dan Ridsdale, a mobile internet analyst at Nomura International.

• BT said it was to receive a £250m refund following a five-year legal battle to reduce its local government business rates bills in England and Wales.

BT also said in a statement that the rates bill next year for its network assets would be cut by £100m to £210m.

The row centred on the valuation of BT's network assets such as street ducts, poles, cables, telephone kiosks, and microwave radio and satellite earth stations.

BT said the case did not cover valuations for properties such as offices and shops. "Traditionally these have been assessed in the conventional way."