The US body that controls the world's internet addresses will vote tomorrow on whether to allow ".xxx" domains for pornography sites.

The Internet Corporation for Assigned Names and Numbers (Icann) will meet tomorrow to discuss the controversial suffix, which could prove to be one of the biggest moneyspinners on the web, but has met fierce resistance from both pornographers and hardline Christian lobby groups in the US.

Plans to create an online red-light district by forcing all internet pornographers to use sites ending in .xxx were voted down in May, after Icann judged them unmanageable.

That decision came as a blow to Stuart Lawley, president of .xxx's sponsoring organisation, ICM Registry, which has spent millions of dollars during a six-year campaign to create a dedicated domain for the porn industry.

If he had been successful, Mr Lawley could have expected to control the rights to some of the world's most lucrative internet assets.

Mr Lawley recently said that ICM also has received more than 1,200 “direct expressions of support from webmasters” in favour of .xxx domains.

The four million websites that make up the global online porn industry are estimated to have generated as much as £6 billion in revenues last year.

As many as two in five internet users visit such sites at least once a month, according to the market researcher comScore.

ICM, which would have charged each .xxx site $60 (£32) a year in registration fees, had argued that the domain would have forced the porn industry to clean up its act, with websites having to abide by a set of rules that would have outlawed malicious behaviour such as sending spam e-mails.

But the plans proved to be highly contentious in Washington, where conservative groups feared they would "legitimise" pornography.

Icann postponed making a final decision on .xxx in August after the White House stepped in only days before a scheduled meeting to discuss the plans.

There were also rumours that Viviane Reding, the EU Information Commissioner, had privately demanded the plans be vetoed.

Anti-porn advocates — including influential US Christian groups — had argued that sites should keep their present .com addresses because the .xxx suffix would only make porn more accessible.

Pornographers, meanwhile, argued that the .xxx system would pave the way for some governments to ban their businesses.

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