Organisers of a major conference on free thought say it has brought together "the largest gathering of ex-Muslims in history".

The International Conference on Freedom of Conscience and Expression took place in London from Saturday to Monday. It was organised by secular and ex-Muslim activist Maryam Namazie. It featured over 70 notable speakers from 30 countries and was dubbed 'the Glastonbury of Freethinkers'.

The conference highlighted the voices of a diverse range of people resisting Islamism. It also passed a Declaration of Freethinkers.

A screening of Islam's Non Believers, a film by Deeyah Khan, showed the persecution facing Ex-Muslims. In a public art protest, 99 balloons represented those killed or imprisoned for blasphemy and apostasy. Some attendees got their bodies painted as part of an artistic activism event.

Debates focused on the relation between Islam and Islamism; the threat posed to universal rights by communalism; and the use of the term 'Islamophobia' in imposing de facto blasphemy laws. There was also discussion of the role of art as resistance and promoting secularism as a human right.

The hashtag #IWant2BFree trended on Twitter over the weekend.

Meanwhile the Council of Ex-Muslims of Britain (CEMB) honoured ten individuals to mark its tenth anniversary. These included Saudi freethinker Raif Badawi; Gita Sahgal and Yasmin Rehman of the Centre for Secular Space; and Bangladeshi blogger Bonya Ahmed.

The conference noted that 13 Islamic states and territories punish apostasy and blasphemy with death, but added that "a tsunami of freethinking and atheism" is "challenging religious fundamentalism, especially Islamism". It criticised human rights organisations and governments for failing to investigate transnational networks which promote violence; examine religious fundamentalist ideology; or defend freethinkers.

The conference also denounced "racism, xenophobia and far-right extremism".

The Declaration of Freethinkers called for six measures to be taken. The killing of apostates and blasphemers should end. Those in prison for thinking freely should be released. Apostasy and blasphemy laws should be repealed.

It should be clarified that freedom of conscience guarantees the right to freedom of and from religion. The right to offend should be protected. And the right to freedom of conscience should be explicitly embedded in human rights documents.

The conference issued resolutions defending Ismail Mohamed, who was prevented from leaving Egypt to speak at the conference; criticising the no-platforming of Richard Dawkins by KPFA radio station; and calling on Pride in London to affirm CEMB's continued place at its event.

The National Secular Society was one of the event's sponsors.

NSS campaigns director Stephen Evans, who attended the event, said: "This inspiring conference gave a sobering insight into the persecution faced by many of those whose only crime is to think for themselves.

"More importantly it provided grounds to hope that their treatment might change. International solidarity can help to defend free thought and win the battle against theocracy.

"The Declaration of Freethinkers provides a clear statement of reasonable steps. Anyone who cares about the freedom to practice or avoid religion should support their implementation wholeheartedly."