Internet service providers have had their knuckles rapped for misleading customers about free web surfing deals.

The Advertising Standards Authority (ASA) is telling ISPs not to advertise services as free if consumers have to pay for any part of the service.

The watchdog is writing to over 100 providers to remind them about advertising regulations and warn them against overselling deals.

The ASA is taking action because it has been inundated with complaints from consumers caught out by ISPs falsely claiming that connection services had no cost.

BT, NTL and service providers Plusnet Technologies and Appleonline.net have all had complaints about their advertising upheld.

Free for all?

In all the cases, the ASA found that the companies were claiming that their web services were free, despite the fact that consumers had to pay to use them.

People signing up for the free services found they received bills for monthly subscriptions or had to pay call charges while online.

The ASA has told the four companies to change their adverts and make it obvious how much people actually have to pay.

"We've written to 100 ISPs asking that they not advertise as free, and do not use the word free if consumers have to pay for any element of the service," said a spokesman for the ASA.

He said the struggle for customers was making some ISPs forget their obligations to consumers.

"They've created a marketplace that's very competitive and they're all trying to carve out their own identity," said the spokesman. "But in the process, consumers are getting confused about what is, and what is not, free."

Advertising obligations

The code of practice of the Internet Service Providers Association, the UK ISP industry body, requires companies to deal honestly with customers and inform them about all costs.

NTL was also taken to task because it underestimated the demand for NTLWorld, its unmetered internet service.

National codes of conduct covering advertising and promotion demand that companies have enough stock, or be able to satisfy demand, before launching special offers or new services.

The ASA said NTL had done a bad job of estimating the demand for its free internet service, and made matters worse by continuing to advertise the service even when it knew some customers would have to wait months to use it.

NTL has been told not to advertise NTLWorld until "it could supply the service to all applicants within a reasonable time".