Politicians in the US have blocked a measure designed to ensure that all are equal on the internet.

The House of Congress voted against an amendment to a key piece of legislation that would prevent telecoms companies from granting higher priority to internet traffic from companies that pay.

Presently telecoms companies are paid by ISPs for the volume of data that travels through their national and global networks of cables and routing equipment, with costs shared among consumers and businesses through subscription fees.

Internet experts fear that the vote against the so-called 'net neutrality' amendment could lead to companies paying telecoms companies to direct traffic to them.

Technology companies and online campaigners have warned against the consequences of failing to defend the principle of neutrality in the US Communications Opportunity, Promotion and Enhancement Act.

Leading online players such as Google and Ebay, as well as websites such as It's Our Net, have warned that an internet where the richest could pay to be found would seriously damage competition, freedom of expression and innovation.

Online campaigns are in full swing to protest against the possibility of a two-tier internet, with Save the Internet publishing a list of reasons why the abandonment of net neutrality is a bad idea.

House of Congress leader Nancy Pelosi told colleagues during the debate that "telecommunications and cable companies [would] be able to create toll lanes on the information superhighway" if the amendment was blocked, the BBC reported.

The legislation will soon be presented to the US Senate.