Prominent scientists have criticised a decision to bar a human rights campaigner from speaking at a university over claims that she could incite hatred on campus.
Iranian-born secularist Maryam Namazie, a member of the Council of Ex-Muslims of Britain, was invited to speak to the Warwick Atheists, Secularists and Humanists society next month.
But the move was blocked by the University of Warwick's Students' Union (SU) amid claims that she is "highly inflammatory and could incite hatred on campus", the society's president said.
SU officials said "a number of flags have been raised" about anti-Sharia campaigner Ms Namazie and her organisation, including from articles written by and about her.
And they added: "We have a duty of care to conduct a risk assessment for each speaker who wishes to come to campus."
The SU highlighted its policies on external speakers, including that they "must not spread hatred and intolerance in the community".
A backlash has been provoked, with scientists Professor Brian Cox and Dr Ben Goldacre among those to condemn the barring of Ms Namazie from speaking on October 28.
Best-selling author Dr Goldacre - a senior clinical research fellow at the University of Oxford - said he would never talk at Warwick.
And on Twitter, Prof Cox said: "We can't allow over-sensitive students to wrap themselves in intellectual cotton wool."
He added: "It is our job as professors to provide students with intellectual armour. No ideas should be beyond discussion."
The society's president, Benjamin David, said they have appealed over the decision. He said Ms Namazie has always campaigned against violence and discrimination.
He admitted feeling "an element of embarrassment" about the barring, adding that restricting non-violent free speech "is the most dangerous of all subversions".
Ms Namazie is a spokeswoman for One Law For All, a campaign against Sharia law in Britain, Fitnah, a movement for women's liberation, and Equal Rights Now, which fights women's discrimination in Iran.
Reacting to the SU's decision, Ms Namazie said she would be formally complaining about its claims after taking legal advice.
She wrote on her blog: "For now, though, suffice it to say that criticising religion and the religious-Right is not incitement of hatred against people.
"If anything, it's the religious-Right, namely Islamism in this case, which incites hatred against those of us who dare to leave Islam and criticise it.
"The Student Union seems to lack an understanding of the difference between criticising religion, an idea, or a far-Right political movement on the one hand and attacking and inciting hate against people on the other.
"Inciting hatred is what the Islamists do. I and my organisation challenge them and defend the rights of ex-Muslims, Muslims and others to dissent."
She added: "These sort of Lefties have one set of progressive politics for themselves - they want gay rights, equality for women and the right to criticise the pope and the Christian-Right, and another for us."
Warwick SU president Isaac Leigh said no final decision has been taken on whether to allow Ms Namazie to speak.
He said: "We have a record of facilitating over 200 speakers a year covering a wide range of topics, many of which are controversial in nature.
"This is part of our role in the development of our members.
"We do everything in our power to ensure that these events take place safely and with any identified risks mitigated. Declining speaker requests is an absolute last resort.
"I would reiterate that the process for reviewing this particular speaker event has not been completed and, once I and senior staff members have reviewed it, a further statement will be made."