The Attorney General of New York State has threatened Comcast with legal action unless it signs up to a pledge to ban its customers from viewing child pornography.

In a strongly worded letter Andrew Cuomo pointed out that major ISPs have already signed up to remove illegal content from sites and news groups listed as containing child pornography.

Cuomo believes that it is unacceptable for Comcast, the nation's second biggest ISP, not to do the same.

"Comcast's unwillingness to sign the Code of Conduct and purge its system of pornography puts it at the back of the pack in the race to fight this scourge, and is likely to surprise Comcast's millions of customers across the country," he said.

"Time is of the essence here, as every day without these measures is another day that this illegal material is sluicing through the internet.

"I am asking you to take another hard look at the agreement that the other five companies have signed and tell me in the next five days whether you will commit to this code."

However, some are questioning Cuomo's stance, especially Usenet users. After Time Warner signed up to the deal the company shut down all access to Usenet because 88 of the thousands of groups carried illegal material.

Other ISPs have also blocked large sections of the venerable and hugely popular bulletin board system.

Comcast has already signed up to a nationwide code of conduct on child pornography, so it is hard to see what reaching a separate deal with Cuomo would accomplish.