Stephen Foley: Why Comcast deal could be a horror show

US Outlook: When Brian Roberts unveiled Comcast's $30bn deal to take control of NBC Universal this week, he declared his cable TV and internet firm had become a leader in the "anytime, anywhere" media that American consumers are demanding.

Indeed it has, and it should worry us all. The deal combines one of the most powerful movie production and TV channel groups into the same company that pipes TV into more American homes than any other. This sort of vertical integration is fraught with conflicts of interest and competition issues, which is why for years regulators have enforced strict rules about how cable firms must offer fair access to all types of channels, not just those they own.

Comcast promises to abide by those rules, of course, but as Mr Roberts himself expressed, this deal is as much about future opportunities for content delivery over the internet as it is about cable TV. It could be tempted to give preferential treatment to NBC content on its internet services, say, by slowing down other kinds of video streaming.

Comcast has form in this area. It was forced to stop interfering with the popular BitTorrent programs used for file-sharing, after its covert practice of slowing down some users' service was exposed in 2007.

Its acquisition of NBC may not fall foul of any explicit competition rules, but it ought to attract prolonged and deep scrutiny by regulators. The Federal Communications Commission has recently expressed its commitment to protecting "net neutrality", demanding internet service providers treat all types of content equally. The rules it is planning will have to be watertight, and Congressional efforts should be stepped up to enshrine net neutrality into law.