A BT television campaign promising users unlimited access to the internet has been banned after advertising watchdogs ruled it was misleading consumers.

The ads, for BT's Openworld Anytime package, showed customers describing the benefits of the service with one saying, "because we're not worried about the cost we just use it any time".

Viewers complained to the independent television commission after BT changed the terms of the service, limiting the amount of internet access to 150 hours a month, which is an average of five hours a day.

BT said the ads had been taken off air on September 22 - a week before the terms and conditions were changed.

It said existing customers would not be subject to the revised terms until November 1 but anyone signing up on or after October 1 would be subject to the five-hour limit.

Before October 1 BT Openworld Anytime customers were entitled to 12 hours online a day.

Upholding the complaints, the ITC said the ad "strongly implied you could access the internet and surf for long periods without the worry of call charges".

The watchdog said the phrase "online session limitations apply" did not convey the extent of the revised terms and conditions that "would drastically reduce" online time.

It concluded that the ad was misleading and banned it from being shown again in its current form.