by her mother that she would be killed

Council of Ex-Muslims leader Maryam Namazie said 'there is nothing more intolerant than religion'

Young Muslims who abandon their faith face violent retaliation and abuse from their families, a support group said yesterday.

The Council of Ex-Muslims of Britain said those born into the religion are often frightened of speaking out – and those that do are in danger of attack.

It said one former Muslim said she was warned by her mother that she would be killed if she said she no longer believed in Allah.

The concern over the risk of reprisals against apostates – those who renounce their religion – was made public at a time of deepening scrutiny of the behaviour of some Islamic communities and institutions.

The risks to Muslims who abandon their religion were set out by former believers and campaigners in an ITV documentary to be broadcast on October 13.

Council of Ex-Muslims leader Maryam Namazie told the makers of the film, Exposure: Islam's Non-Believers: 'They see us trouble-makers, deviants, apostates and blasphemers. There is nothing, nothing, more intolerant than religion.'

One former Muslim, who identified herself only as Sadia, told the documentary makers: 'I remember saying to my mum, I don't believe in God any more. And her saying, 'you can't tell anybody else because they'll kill you, we are obliged to kill ex-Muslims'.

'And that it would put me at extreme risk if anybody else was to find out, so that conversation ended there.'

Young Muslims who renounce their faith are said by campaigners to risk discrimination, ostracism, psychological abuse and violence. Some are said to have suffered abuse by family members and to be in danger of suicide or self-harm.

Apostasy is frowned on in most Muslim countries and can be punished in some with the death sentence. The documentary makers allege that critics of Islam have been murdered in Bangladesh and that atheists in the country are under threat both from the government and from Islamist gangs. The Council of Ex-Muslims said that in Britain radical Islamist protesters try to shut down meetings or events.

The inquiry was launched by Theresa May (pictured) when she was at the Home Office

Miss Namazie, an Iranian-born secularist activist, said: 'The internet and social media are doing to Islam what the printing press did in the past to Christianity, because it is one way in which masses of people can connect with each other and can hear ideas that are taboo and forbidden.'

A series of issues relating to some Islamic communities and institutions have come into the public domain in recent times.

One revolves around so-called honour killings, in which Muslim women have been murdered by their own families after marrying non-Muslims or others disapproved of by relatives.

The decision of an Islamic school to launch a court challenge against a critical inspectors' report – and the ruling of a judge that banned the school from being named – has led to a spotlight on the links between some schools and extremists.