The Ukip leader, Nigel Farage, has distanced himself from the views of his own immigration spokesman, Gerard Batten, after the London MEP proposed a special code of conduct for Muslims.

Ukip stressed that asking Muslims to sign such a document had never been one of its policies, even though the launch of Batten's "proposed charter of Muslim understanding" used to be promoted on the party's website.

Batten, who was on Wednesday campaigning for Ukip in the Wythenshawe and Sale East byelection, told the Guardian this week that he could not see how any "reasonable, normal person" could object to signing the charter, which calls on Muslims to accept equality, reject violence and accept the need to modify the Qur'an.

In a separate video interview from 2010, Batten also proposed a ban on new mosques across Europe, suggested Muslim countries should not be "appeased" and warned of the threats of having "two incompatible systems living in the same place at the same time".

A number of MPs and MEPs condemned Batten's comments, with Robert Halfon, a Tory MP, accusing him of taking an "unbelievably sinister" position comparable to asking members of the faith to wear a yellow star.

Halfon, who is Jewish and has spoken out repeatedly against Islamic extremism, said he considered Batten's views frightening.

He tweeted: "Big difference [between lawful] Muslims & extreme Islamists. UKIP MEP Batten's statement a 1st step to wearing a Yellow Star."

Sarah Ludford, a Liberal Democrat MEP for London, also criticised the comments, saying they "rip apart Ukip's pretence" that it treats everybody equally.

"His offensive blanket stereotyping of Muslims as jihadists speaks volumes about Ukip's extremism and should warn voters that voting Ukip means associating with hatred and Islamophobia," she said.

Two prominent Muslim MPs, Sadiq Khan and Rehman Chishti, condemned the "offensive" idea of a charter for Muslims. Chishti said Batten, who is Ukip's immigration spokesman, should not be allowed to stand again as an MEP.

Meanwhile, Syed Kamall, the Conservative leader in the European parliament, who is a Muslim, left a letter on Batten's empty seat at the parliament chamber in Strasbourg, offering him a guarantee that he had no intention to commit acts of violence or promote extremism.

"Do you have a form I can sign already?" asked Kamall. "I am anxious to assure you that I have no intention of mounting any attacks on unsuspecting infidels, nor of attempting to radicalise you or anyone else.

"If the forms aren't ready yet, perhaps you would take this note as my guarantee? My wife and family would be most reassured to know you will allow me to stay in Britain, especially since I was born here. Please feel free to drop into my office to discuss this over a cup of tea. I promise you will be entirely safe."

Mohammed Shafiq, the chief executive of Muslim thinktank the Ramadhan Foundation, said asking one particular community to sign a "loyalty pledge" against violence was "offensive and an insult to all decent people".

In response to Batten's comments, Farage said in a statement: "This was a private publication from Gerard Batten in 2006 and its contents are not and never have been Ukip policy. No such policy proposals would have been accepted by Ukip in any case. Ukip believes in treating people equally."

It comes as Farage tries to rid the party of "Walter Mitty" types after a stream of controversies. These include the party's suspension of a councillor for blaming flooding on gay marriage and the ejection of the MEP Godfrey Bloom following comments about women and sending foreign aid to "bongo-bongo land".

It also comes the day after Ukip distanced the party from Mujeeb ur Rehman Bhutto, its former Commonwealth spokesman, who was revealed by BBC Newsnight to have once been part of a kidnapping gang.

With Ukip hoping to top the polls in May's European elections, Batten is top of the party's MEP candidate list for London, having passed a round of psychometric testing to make sure his views were acceptable.

Batten told the Guardian he had written the charter in 2006 with a friend, who is an Islamic scholar. Asked on Tuesday whether he still believed Muslims should sign the charter, Batten said: "I don't suppose the pope would disagree with it or the archbishop of Canterbury or anybody else. So why should they feel aggrieved that they might be asked to sign? They don't have to. If they don't believe in those five points, they don't have to sign it."

In a press release from the time, published on Ukip's website, Batten calls on Muslims to sign a five-point affirmation, in which they would promise to accept equality, reject violence in the name of religion, and accept a need to "re-examine and address the meaning and application of certain Islamic texts and doctrines".

Asked why Muslims had been singled out, rather than followers of other faiths, Batten said: "Christians aren't blowing people up at the moment, are they? Are there any bombs going off round the world claimed by Christian organisations? I don't think so."

In a statement to the Guardian, Batten later said: "I would expect the fundamentalists to agree with me that democracy is incompatible with fundamentalist Islam. Moderate Muslims have to decide which side of the argument they are on.

"Who is in favour of jihad? Apart from the jihadists of course? I was, and still am, happy to speak out against it. It is amusing that the Guardian equates being opposed to extremism and jihadism as 'overlapping with the far-right'. So are leftwing liberals in favour of jihad? If not, do they overlap too?"