Consumers are being warned to be wary of unsolicited emails which invite them to connect to a particular website promising such topics of interest as celebrity or sports news.

In several recent cases, users have agreed to connect to such websites without being informed that in doing so, they would be cut off from their current Internet Service Provider and instead switched to a premium-rate ISP service that could cost upwards of £1.50 a minute.

Unscrupulous companies are taking advantage of the fact that users keen to connect to an advertised website will not read the smallprint regarding costs - especially when it runs into multiple pages. They are more likely to click on the I agree' check boxes in order to connect to the site of interest as quickly as possible.

Once that box has been checked by a user, they inadventently download a dialler program which changes their existing ISP connection to reconnect to the premium-rate service instead.

The dialler will remain on a computer until it is deleted, so will often pop up only to be clicked on again without the consequences being realised.

Because an alarming number of people are being caught in these scams and are ending up with enormous telephone charges, the Independent Committee for the Supervision of Standards of Telephone Information Services (ICSTIS) has stepped in to set down clear rules to protect consumers.

As well as now requiring permission from ICSTIS to trade, companies that offer premium-rate call charges must ensure that all information on call costs is clearly and prominently displayed on-screen alongside a clock to show the minutes that a user has been connected.

Call costs must not exceed £20. Anybody aware of companies breaching these guidelines should report them to the ICSTIS at www.icstis.org.uk.