Hizb ut Tahrir (HT), a legal Islamist group in the UK with members and affiliates known to have previously run tax payer-funded schools and held elected positions in British universities, is operating alongside Al-Qaeda in Syria.

Aided by the Nusra Front, Al-Qaeda’s franchise across the Middle East, HT is launching attacks on secular anti-Assad groups and civil activists in the northern Syrian city of Aleppo.

Hundreds of members descended on secular demonstrations in an opposition-controlled neighborhood called Bustan al-Qasr on Friday. Photos show them confronting the peaceful, non-Islamist demonstrators and a well known activist was arrested and severely beaten the next day, The Times reports.

They stated their commitment to the idea that revolution’s objective should be to establish a ‪‎Caliphate, their opposition to secular bodies like the Syrian National Coalition, rejected any secular solutions and denounced pluralism in Islam.

In a video of the demonstration they are heard chanting, “we want an Islamic Caliphate” and “It is for the sake of Allah (the revolution) not for the authorities of the state.”

HT is outlawed across most of the Arab world as a terrorist organization and in many western nations, but remains legal and very active in the UK. Tony Blair and David Cameron both vowed to ban the organization but fell silent on the issue once in government.

Their previous UK leader, Omar Bakri, once called for Muslims to assassinate John Major on the eve of the first Gulf war. “We will celebrate his death,” he told the Daily Star.

The group has long been a powerful force at Westminster University, where Mohammed Emwazi (“Jihadi John”) attended, and where Tarik Mahri was elected to the role of president of the student union, despite his links to HT.

Ed Balls was dubbed “The minister for Hizb ut Tahrir” when education secretary under Tony Blair, after he directed £113,000 of public money to schools controlled by HT.

HT was founded in 1953 with the aim of establishing a caliphate under Islamic law, has spread to 50 countries and by one estimate has about one million members. The UK branch has existed since 1986.

The group claims to be non-violent, however they oppose any western influence in the Muslim world, reject democracy, freedom of religion, human rights and female equality and have been linked to violent extremism many times.

HT’s spokesman in the UK, Taji Mustafa, denied his group is working with the Nusra Front in Aleppo: “Hizb ut-Tahrir is an independent organisation and is not linked to Nusra Front or any other movement… We reject the insinuation that [we] are involved in attacks in Syria,” he said.