A Ukip-authorised Christian group has been condemned for distributing a newsletter that refers to gay people as depraved sodomites and argues that they could be converted from a state of vice.

On Tuesday night, the party distanced itself from the publication by the Christian Soldiers of Ukip but was facing calls to categorically cut all ties with the group, which holds events annually at the party’s conference and has previously published articles by the Ukip leader, Nigel Farage.

The comments emerged in an article about last year’s Manchester Pride event, which was described in the Christian Soldiers newsletter as an “annual parade of depravity”. It said: “Thousands of people proclaiming their pride in their depravity paraded through the streets watched by multiple thousands of supporters applauding the display of wickedness and seeking to drown out the voices of the few crying in the wilderness.

It went on to suggest that gay people can be “converted” away from their “vice”. “There are those who say that we shouldn’t be witnessing at these events because they are given over by God to this vice as per Romans Chapter 1. While this is undoubtedly true of many, it is not true of all because homosexuals are being converted. The same could be said of most sinners.

“Please write to Asda and tell them that as a Christian you will no longer shop with them because of their support for the ‘gay march’ in Manchester which took place in front of little children during the day.”

The newsletter drew attention to the presence of police officers and teachers at the parade, suggesting this was inappropriate. “There were two floats representing teachers unions: the NAWT and the NUT. As the NUT passed the witness, one of their number taunted the Christians over a loudspeaker. He kept repeating: ‘We teach your children.’ One wonders just how many Christians who send their children to state schools are bothered by this. Well they ought to be!”

Ukip has been attempting to stress its openness to lesbian, gay, bisexual and transgender members despite its opposition to same-sex marriage and controversies over homophobic comments made by some associated with the party.

A Ukip spokesman described the Christian Soldiers group as “authorised but not official”, adding: “They do not represent the party or its policies. This leaflet was recently brought to our attention. Authorised groups are not allowed to invent Ukip policy and we do not consider that this leaflet is of an acceptable standard to be associated with the Ukip brand.”

Peter Tatchell, a leading gay rights campaigner, called on the party to go further and discipline those involved in the homophobic remarks. “These intolerant, inflammatory views are very similar to those expressed by the British National party,” he said. “These opinions are not isolated and they are being repeated by Ukip members all over the country.”

Elizabeth Biddulph, a leading member of Christian Soldiers of Ukip, stood by the group’s decision to publish the article, which she said objected to the way some teachers on the pride march had shouted at Christian protesters. “It’s the shouting. It was the way these men who were half dressed were taunting the Christians who were there singing hymns,” she said.

Asked about whether it was endorsing the idea of gay people being “converted” away from vice, she said: “It’s for Christians. Most of them are born again and that is their belief. It’s free speech between people who share the same view unless we live in Soviet Union or Nazi Germany censoring what people believe.”

She added that the newsletter had a disclaimer on the back making clear that its views should not be taken as those of Ukip and the party had not previously objected to any of its newsletters.Meanwhile, a Ukip general election candidate has quit in relation to an internet posting that referred to gay people as “perverts” and “paedophiles”.

Donald Grewar apologised for his “foolishness” after it was reported that he backed a post about same-sex marriage on the BNP website and another post by the English Defence League calling for “no surrender to militant Islam or political correctness”.

Ukip also found itself at the centre of a controversy about religious rights after the party backed the British Veterinary Association and RSPCA in calling for a ban on non-stun slaughter.

A Ukip spokesman said on Tuesday : “We see no reason why religious groups should not take into account the concerns of animal welfare when carrying out slaughter. We find the government response to this issue is weak, lazy and bordering on spineless. It says it would ‘prefer’ animals to be stunned before slaughter but that it must ‘respect the rights of Jewish and Muslim communities to eat meat in accordance with their beliefs’.”