Home Office interpreters have deliberately jeopardised asylum cases because they personally disagree with the claimant, it was alleged on Tuesday.

A report into asylum claims in the UK on religious freedom grounds pointed to a "lack of professionalism" from some interpreters hired by the Home Office, which could lead to people being sent to their deaths if returned to their country of origin.

Speaking after the launch of the report on Tuesday, Bishop Angaelos, general bishop of the Coptic Church in the UK, told Christian Today: "At best it is ignorance and at worst we have heard occasions where it has been intentional persecution and an intentional undermining of the case."

He said it was the exception rather than the rule but that it "needs to be investigated at once".

Angaelos said on at least one occasion a Muslim interpreter had condemned the claims of an individual who had left Islam. "While it is only a statistic and may only be one case, for this one case it is a matter of life and death," he said.

He was quick to praise the Home Office's "good intentions" with updates to the official guidance but said more training was needed for people handling asylum cases.

The report was compiled by the Asylum Advocacy Group (AAG), of which Angaelos is chair, and the All-Party Parliamentary Group (AAPG) on international freedom of religion and belief.

It clearly demonstrated a disparity between what the Home Office says in its official guidance and what actually happens in interview rooms and asylum assessment centres.

In one instance an Ahmadi Muslim who had fled persecution said he felt forced to answer the interviewer's questions in his broken English because he thought the interpreter had missed out things he had said or had not translated them properly. The applicant felt this may be because the interpreter "did not personally agree" with him.

Ahmadi Muslims are notoriously persecuted by other Muslim groups who consider them heretical. Many have fled India, Pakistan and Indonesia where Human Rights Watch has said they face systematic harassment and intimidation by government officials.

The report criticised the "ignorance" of caseworkers and interpreters who worked with asylum claimants and said more training was needed. A lack of religious knowledge meant Christian converts were asked "Bible trivia" questions from crib sheets which the report said was "too simplistic a way to judge if an individual is, for example, a genuine convert".

It read: "This report's findings signal a lack of understanding and misperceptions of religion and belief among deicison-makers working within the UK asylum system."

Baroness Berridge, chair of the AAPG, acknowledged the Home Office had to make decisions that are "some of the most difficult to make" and praised its efforts in updating the official guidance. But she told Christian Today the problems surrounded "the practises of the interviewers".

Asked about the case of the Muslim interpreter and the Ahmadi claimant she said these were "important difficulties" and added it was about creating the right environment for traumatised individuals to tell their stories.

"If you are someone who is claiming to be a victim of sexual violence, as a woman you have the right to ask for a caseworker and an interpreter who are female," she told Christian Today. "It is difficult with limited resources but we have to make sure the situation is such that we get the best version of the story out of the person first time around."

Christian Today contacted the Home Office for comment but had not received a response at the time of publishing.