Following an appearance on the BBC's The Big Questions last Sunday, the Liberal Democrat parliamentary candidate for Hampstead and Kilburn Maajid Nawaz tweeted an image from the web comic Jesus & Mo along with the message: "This Jesus & Mo @JandMo cartoon is not offensive & I'm sure God is greater than to feel threatened by it".

Nawaz, who is a Muslim and executive director of the counter-extremism think tank the Quilliam Foundation, wrote the tweet as part of a discussion on the BBC's decision not to show t-shirts worn by two members of The Big Questions audience which depicted scenes from Jesus & Mo. Somewhat predictably, Nawaz immediately received death threats via social media. But the backlash has not only involved threats of violence, but also calls for the Liberal Democrats to deselect Nawaz as a candidate in the next general election.

After criticism from a fellow member, Mohammed Shafiq, who sits on the Lib Dems' Ethnic Minority committee, a petition was launched, appealing to the party leader Nick Clegg to remove Nawaz as the candidate for Hampstead and Kilburn. The lengthy open letter that accompanies the petition, which has gained more than 20,000 signatures, argues that Nawaz should be deselected on the basis of the "extreme amount of insult, hurt, and anguish" caused to Muslims by the Jesus & Mo cartoon.

While the call for Nawaz's deselection has clearly attracted some support, a counter-petition appealing to the Liberal Democrats to defend their candidate has received over 6,000 signatures, and numerous commentators have called on the party to uphold the right to free expression. "We simply can't have a climate where politicians are intimidated into silence by people who believe they have a right not to have their religious sensibilities offended," said the National Secular Society's Stephen Evans. "Anything other than complete Liberal Democrat support for Maajid could have a very chilling effect on free speech in this country."

The fact that the row has occurred among Liberal Democrats has added a touch of irony to the issue – this was noted by Telegraph's Tom Chivers, who wrote last week that "if the Lib Dems, for one second, consider bowing to this illiberal nonsense and dropping Nawaz, then they don't deserve the prefix 'liberal'."

Thankfully, Nawaz has received a significant level of support from within the party. Stephen Tall, co-editor of the Liberal Democrat Voice site, wrote a post in defence of Nawaz soon after the controversy broke out, and Nick Clegg has now expressed his support, using a letter to the petitioners to condemn the death threats and point to the party's liberal heritage in defence of free speech:

“We fundamentally believe in freedom of expression in an open, liberal and free society and therefore strongly defend Maajid’s right to express his views.

“I’m sure it goes without saying that the death threats and threats of violence Maajid has received are totally unacceptable, and I’m sure you will join me in whole-heartedly condemning them.”

This is not the first time that the Jesus & Mo cartoons have led to disputes over the boundaries of free speech. In 2012, a row broke out at University College London over the use of a Jesus & Mo image on the student atheist society's Facebook page, while last year two members of the London School of Economics Atheist, Secularist and Humanist Society were threatened with disciplinary action for wearing Jesus & Mo t-shirts at the college's freshers' fair. The LSE dispute eventually resulted in the university issuing a formal apology to the students.