BTopenworld is to place new limits on the amount of time its Anytime and Surftime customers can spend online.
From 1 November, Anytime users will be restricted to a monthly quota of 150 hours online per month. If they exceed that limit, they will be charged on per-minute basis. They are currently restricted to 12 hours online in any 24 for a flat fee of £15.99 per month.
Surftime users, who currently pay £6.99 per month for evening and weekend access, will be limited to 120 hours per month during those periods, with a similar pay-as-you-go element for anyone exceeding that cap.
Customers will be able to carry over up to 50 unused hours from the previous month, meaning that Anytime customers may be able to use up to 200 hours in any given billing month and Surftime users may be able to use up to 170 hours. All subscribers will begin November with an additional 50 hours on top of their monthly limit.
The limitations are the latest effort in a long-running campaign by unmetered access providers to deter heavy users from spoiling the party for light surfers, and to ensure their business models are viable.
Duncan Ingram, senior vice president of BTopenworld, said: "We're doing this to secure our ability to provide a high quality of service, and to provide value for money. One hundred and fifty hours is virtually unmetered. The average Web user spends around nine hours online per week, according to Oftel. We've talked to customers who've said 100 hours is more than enough. We're being open, honest and fair with our customers."
The company says that average customer use during June was 43.9 hours, and estimates that the limits will only affect three per cent of its users. They are desigend to stop what Ingram called a "tiny minority" degrading the service for other users..
But the move is as much about BT's determination to create a sustainable business model as it is about customer satisfaction.
Ingram said: "We believe that the ISP industry as a whole is struggling to come up with a viable business model. Under the current conditions, we couldn't guarantee that ours would be viable going forward."
Ingram denied that the company is attempting to drive heavy users onto broadband ADSL services, over which BT holds a near-monopoly. ADSL offers an always-on connection, but BT's ADSL services cost roughly twice as much as Anytime, at £29.99 per month. Some ISPs resell BT's wholesale ADSL for lower prices.
The move follows on the heels of AOL's announcement on Friday that it will stop flat-rate access for its users who do not subscribe to BT, Telewest or NTL telephone services. AOL said that the wholesale unmetered offerings of telcos such as Kingston Communications, Telewest Eurobell, Jersey Telecom, Guernsey Telecoms, Manx Telecom and WightCable were not "sustainable".