It is expected that the religious ruling, which will be drafted this week, will effectively outlaw the bombers among Muslims by stating the attacks were a breach of the most basic tenets of Islam.
Senior community leaders believe they must try to deflect another wave of revenge attacks by undermining the religious basis of the terrorists' alleged Islamist ideology and, significantly, by questioning their right to describe themselves as Muslims.
The move follows a decision taken late on Friday night at an emergency summit attended by about 100 of the country's most prominent Muslim leaders, held in private at East London Mosque.
Sir Iqbal Sacranie, general secretary of the Muslim Council of Britain (MCB), said: "Those behind this atrocity aren't just enemies of humanity but enemies of Islam and Muslims. The people at the receiving end of this, both as some of the victims of the bombing and victims of the backlash, are Muslims."
The proposal was thrashed out amid growing fears that British Muslims face violent reprisals for the bombings which have killed more than 50 people and wounded another 700 people.
Several religious centres, including a Sikh temple and a mosque in Leeds, have already been attacked, and several Muslims have reportedly been assaulted in southern England and north London.
Muslim leaders have also been sent hundreds of threatening emails, thought to have been orchestrated by neo-Nazi groups. In the aftermath of the 11 September attacks on New York and the Pentagon, hundreds of British Muslims were assaulted, one fatally, with mosques firebombed and desecrated.
The statements - the first of their kind issued by British Muslim leaders - mark a turning point for the UK's Islamic scholars. Under Islamic law, it is impossible to strip someone of their right to call themselves Muslim. Unlike the right of Catholic popes to excommunicate, in Islam that power is reserved to God.
Senior clerics and scholars are, however, able to repudiate a Muslim's actions and to discredit the Islamic basis of their behaviour. This approach has been highly controversial, however, after Islamic scholars ruled the Ahmadi sect were not Muslims because they believe Mohamed was not the final prophet and that their founder was the messiah.
The MCB's official spokesman said: "If these bombers are found to be Muslims, we will make it clear we utterly dissociate ourselves from them - even if they claim to be Muslims or are acting under the mantle of the Islamic faith. We reject that utterly."
Within hours of the bombings on Thursday, senior Islamic scholars abroad condemned the attacks in Egypt and Saudi Arabia condemned the bombing as un-Islamic.
One of the first was Yusuf al-Qaradawi, the controversial Egyptian cleric who met Ken Livingstone last year and who was accused earlier this year of supporting suicide bombing and the killing of homosexuals.
Sheikh al-Qaradawi said that Islam "denounces in the strongest possible terms the shedding of the sanctified blood of innocent and protected people."
He said the bombings were "evil acts characterised by barbarity and savagery, which are condemned by Islam in the strongest of terms, for Islam is extremely clear about the prohibition of taking human life".
Signed by dozens of prominent Muslim bodies, mosques, Islamic scholars and community groups, the MCB will also state that Muslims have a moral duty to help the police catch the perpetrators.
Community leaders are also under intensifying political pressure to take these steps.
Murad Qureshi, the only Muslim member of the Greater London Assembly and a former Labour councillor in Westminster, said: "If there was a fatwa issued, I would welcome it.
"It's about time we put clear distance between ourselves and so-called Muslim leaders like Osama bin Laden, who has been able to dictate the whole agenda with his video nasties."
Mr Qureshi, who was brought up close to Edgware Road, scene of the third of Thursday's Tube bombings, said the Arab-dominated area was now extremely tense.
"It is undoubtedly subdued," he said.
Lined by Lebanese, Moroccan and Arab restaurants, the road is also close to Britain's "senior" mosque, at Regent's Park.
In common with mosques across the country, the mosque was unusually quiet during Friday prayers, with little to be seen of the politically-active radical groups that usually leaflet worshippers there.
Many community leaders reacted last week by urging Muslims to stay indoors, travel in groups and avoid areas around pubs at closing time - advice which is now being rejected as too defensive.
Mr Qureshi and Sir Iqbal Sacranie said they plan to resist efforts to demonise Muslims - a theme picked up last week by Trevor Phillips, chairman of the Commission for Racial Equality.
Mr Phillips said: "There's not a dividing line between Muslims and Londoners. The dividing line is between those who commit these acts and those who don't."
Mr Qureshi said: "It's important we don't feel we have to apologise for Thursday's attacks. We're not talking about Muslims here. We're talking about a bunch of nutters. The time has come to debunk the idea they are sanctioned by Islam."Reuse content