The policy is being developed despite recent warnings from a group of international experts on radicalisation that such strategies are likely to be "largely ineffectual".

The Office of Security and Counter-Terrorism (OSCT), a 200-strong Home Office unit created 18 months ago, has said in meetings it wants to "flood the internet" with "positive" interpretations of Islam. It plans to train government-approved groups in search engine optimisation techniques, which it's hoped will boost their profile online and battle radicalisation.

Organisations such as Quilliam, which describes itself as "the world's first counter-extremism think tank" and is jointly led by former radical Ed Husain, have been identified as potential beneficiaries of the work. A spokesman for the group declined to comment.

Officials are currently understood to be in the early stages of the programme.

A Home Office spokesman confirmed search engine optimisation training is part of the government's anti-radicalisation strategy. "In order to support mainstream voices, we work with local partners to help develop their communication, representational and leadership skills," he said.

"This support could include media training, which can help make their voices heard more widely, and support the development of skills which allow communities to be more effective in debate."

The effectiveness of search engine optimisation in reducing traffic to extremist websites has been dismissed by academics however. In March, a report produced by the International Centre for the Study of Radicalisation (ICSR) said young Muslims were much more likely to be directed to extremist material online by web forums and offline associates than by Google or other search engines.

"Tweaking the results for supposedly extremist terms would be largely ineffectual, not least because it is unlikely that any but the most callow wannabe terrorist would use a mainstream search engine to find banned material," the authors wrote. ICSR is a collaboration between British, American, Israeli and Jordanian universities.

The embattled Home Secretary Jacqui Smith recently launched the government's updated counter-terror strategy, CONTEST 2, which put heavy emphasis on countering extremist views. In December she said: "We will host a core network of people who will put forward positive messages from the British Muslim community on the internet, directly challenging the extremists that set out to groom vulnerable individuals."

The OSCT plans to help Islamic groups manipulate their Google rankings appear to be a part of that "direct challenge". The Home and Foreign Offices also set up the secretive Research, Information and Communications Unit, which actively produces and distributes propaganda against extremist groups.

Search engine optimisation techniques are used widely by news organisations and online merchants to make websites more attractive to Google's ranking algorithm. They are broadly classified into legitimate "white hat" manipulation methods such as using common keywords in page titles, and "black hat" methods, which try to trick search engines into giving undeservedly high rankings.

When Google detects black hat methods it bans the page from its index, as it did to the German website of car maker BMW in 2006. ®