BT Openworld has sent out an email to its unmetered internet access customers warning them that their service has been severely limited, while at the same time offering them a broadband upgrade deal.

The unmetered package has never really lived up to its name, with customers' daily surfing time limited to 16 hours.

But now customers will be limited to 12 hours in any given 24-hour period, in order "to maintain the quality of our unmetered internet access service for the majority of our customers".

BT Openworld's spokesman was unavailable to comment.

Rival ISP Freeserve's unmetered Anytime package, costing £13.99, clearly states in its terms and conditions that users will be cut off "if the user makes abnormal demands on the service".

"We will terminate the package for excessive use but we impose no specific hourly limitations," said Freeserve spokeswoman.

"Obviously it's not completely unlimited access, despite its name. For that customers need to switch to broadband," said an spokesperson at telco watchdog Oftel.

BT has leapt on the problem and decided to take its chance to push more customers toward its broadband services, which just happen to be a good deal more expensive that its unmetered package.

Customers who switch to broadband (home 500 Plug&Go) services will find their bank accounts credited with £90 incentive — money that could be used to cover the £85 fee for equipment installation. Line activation, which is usually £65, is free until the end of June.

So while customers who upgrade from unmetered access will have £5 in hand, it won't be for long; broadband costs £14 a month more (currently £29.99), which is an extra £168 per year.

"Obviously customers have a choice to switch to broadband, and a cheaper option does still exist," added Oftel.