'Despite an official ban, the Muslim Brotherhood is Egypt's largest and most organised opposition movement. The interior ministry blamed the organisation for rioting that took place on Tuesday, saying that a number of protesters "particularly a large number of those affiliated with the Muslim Brotherhood… began to riot, damage public property and throw stones at police forces".
However, their numbers in the protests is unclear. The conservative leadership decided not to fully endorse the demonstrations to the anger of some younger supporters. A senior spokesman, Essam el-Erian, said he did expect large numbers of the organisation's members to participate of their own accord, and called on them to stick to peaceful methods. Leaflets outlining its political demands were distributed at the rally.
Until last year, Muslim Brotherhood members (running as independent candidates) held one-fifth of seats in the last parliament. But it lost its representatives in the 2010 parliamentary election. After a first round of voting was marred by serious fraud and violence, it decided to boycott the second round.
In the past, the group has proven able to draw large crowds out onto the streets but has mostly avoided directly challenging the government. It has organised large protests against Israel's war in Gaza and the US-led war in Iraq, for example.'
Oddly the BBC don't find room to tell us the motto of the Muslim Brotherhood, which is "Allah is our objective. The Prophet is our leader. The Qur'an is our law. Jihad is our way. Dying in the way of Allah is our highest hope."
For a slightly less starry-eyed view of The muslim Brotherhood, take a read of this rrom the Middle East Forum.