Some teachers are “self-censoring” to avoid offending religious pupils, according to a poll.

A YouGov survey of more than 1,000 teachers conducted for the Policy Exchange think tank found 16% of them admitted to having self-censored in order to avoid causing religious offence.

The centre-right think tank claims this has created a “de facto blasphemy code in schools across the country”.

It says the Batley Grammar School incident, where a teacher was forced into hiding and received death threats after showing a class a picture of the prophet Muhammad, has “clearly scared the teaching profession”.

Some 55% of teachers polled said they would never use an image of the Islamic prophet in class and a further 9% cited the Batley incident as the reason they would not do so.

Our teachers – and their pupils – deserve better than this.

Half of teachers said there would be a risk to their safety if protests similar to the ones which sprang up outside the school gates in Batley occurred, with one in five saying there would be a “very big risk”.

The region with the highest percentage of teachers suggesting there would be a “very big risk” was Yorkshire and the Humber, where the Batley incident took place, at 33%.

Three quarters of teachers said that if protests broke out, they would be “damaging” to the teacher involved, with around four in 10 (39%) suggesting they would be “very damaging”.

The think tank claims that despite this, parliamentary questions reveal the Government has “abandoned” plans for new guidance to support schools on the issue.

Former home secretary Suella Braverman had promised “clearer and firmer” guidance for schools after a 14-year old autistic pupil from Kettlethorpe High School in Wakefield was sent death threats after minor damage was caused to a copy of the Koran.

The think tank said he had brought a copy of the book into school as a forfeit for losing a video game with friends.

Only 36% of teachers said their schools have guidance to avoid causing offence from teaching materials or lesson content while four in 10 teachers (40%) said their schools do not have any such guidance.

The Department for Education (DfE) has said existing guidance is adequate and suggested in a written statement to the Home Office that such guidance is not being developed, the think tank said.

Policy Exchange has said any new guidance should uphold teachers’ freedom of expression within the law, stop schools from suspending teachers who use materials some religious people may find offensive as long as they have “legitimate teaching objective”, stop pupils accused of causing religious offence from being suspended and protect a teacher’s identity in the event of protests.

Organisations that publicly name accused teachers should “be held accountable” through the Charity Commission or the courts, the think tank added.

Former education secretary Nadim Zahawi said: “The polling for Policy Exchange shows that one in 10 teachers are less likely to show an image of the Prophet Muhammad in lessons as a result of the Batley Grammar School protests… Our teachers – and their pupils – deserve better than this.

“We owe it to them to support them to provide a secure environment where open, honest and free discussion is not only permitted, but actively encouraged.”

A total of 1,132 teachers from across the UK took part in the survey.

A Department for Education spokesperson said: “We have been clear that it is never acceptable to threaten or intimidate teachers.

“All schools are required to promote our shared fundamental British values including individual liberty, mutual respect and tolerance.

“Teachers can cover a full range of issues, ideas and materials in their curriculum, including where they are challenging or controversial, subject to their obligations to ensure political balance.”