Dr Tahir ul-Qadri, from Pakistan, says his 600-page judgement, known as a fatwa, completely dismantles al-Qaeda's violent ideology.

The scholar describes al-Qaeda as an "old evil with a new name" that has not been sufficiently challenged.

The scholar's movement is growing in the UK and has attracted the interest of policymakers and security chiefs.

In his religious ruling, delivered in London, Dr Qadri says that Islam forbids the massacre of innocent citizens and suicide bombings.

Although many scholars have made similar rulings in the past, Dr Qadri argued that his massive document goes much further by omitting "ifs and buts" added by other thinkers.

He said that it set out a point-by-point theological rebuttal of every argument used by al-Qaeda inspired recruiters.

The populist scholar developed his document last year as a response to the increase in bombings across Pakistan by militants.

'Heroes of hellfire'

The basic text has been extended to 600 pages to cover global issues, in an attempt to get its theological arguments taken up by Muslims in Western nations. It will be promoted in the UK by Dr Qadri's organisation, Minhaj ul-Quran International.