Parliamentary candidate Maajid Nawaz has received violent threats after posting a cartoon to Twitter featuring Jesus and the Prophet Mohammed.

There have been calls from Ramadhan Foundation's Mohammed Shafiq, Muslim commentator Mo Ansar, and Bradford Respect MP George Galloway for the Liberal Democrats to drop Nawaz as a parliamentary candidate.

Nawaz, a Muslim, is due to contest Hampstead and Kilburn next year.

The cartoon at the centre of the row shows Jesus and the Prophet Mohammed saying "Hey" and "How ya doin'" to each other.

Nawaz, also co-founder of anti-extremism think tank Quilliam, said he posted it to his Twitter timeline to encourage a debate among Muslims about what is acceptable to their faith.

He said on Twitter that he did not find the cartoon offensive.

The backlash against him has included threats of violence, reportedly including beheading, and when he posted the cartoon on his Facebook page, one response read: "Maajid Nawaz. Dont ever come to Isleworth Hounslow or the surrounding areas you b***** coconut! Or better yet do i'd love to see the area unite capture uou and bring you to justice peraonally [sic]."

Responding to the row on Twitter, Nawaz has made repeated calls for calm on his Twitter page.

"No one's interests to blow this out of proportion. Will not further integration efforts of my fellow Muslims in UK. May we calm down please?" he said.

In another tweet he said: "One good thing that's come out of this furore is the healthy debate by some mature people in the middle. It's the only way to move forward!"

Since the tweet on 12 January, two petitions have been launched, one by angry critics calling for him to be dropped by the Lib Dems, and another by those who back Nawaz calling upon the Lib Dems to show him their full support.

The Liberal Democrats have not commented on the row.

Criticising Nawaz's decision to tweet the images, Mohammad Shabbir, a Muslim and councillor for Heaton Ward, Bradford, suggested freedom of speech should not mean saying or doing things that others are likely to find offensive.

Writing on his blog, Shabbir said: "So Majid Nawaz tweets the images. I wonder why? For me it seems that it's just plain electioneering or at least an early start or perhaps as someone else has said to get the fatwa label.

"For me as a Muslim I uphold the right of people to their beliefs and values and the idea of free speech however I remind myself and everyone that indeed 'civilisation is consideration' anything other is just plain vulgarity and should be labelled as such. Most certainly it is not a way to create a just and equitable society free from hate."

The National Secularist Society is among those backing Nawaz and the petition in support of him.

Stephen Evans, campaigns manager at the National Secular Society said: "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. Anything other than complete Liberal Democrat support for Maajid could have a very chilling effect on free speech in this country."