Britain’s largest teachers’ union says school children are using social media to bombard teachers with homophobic abuse.

A growing number of children, some as young as four to seven-years-old, are targeting staff with offensive language and comments about their race, sexual orientation and appearance.

In a survey of 7,500 members, NASUWT found that the problem is widespread, with 21% of teachers polled revealing that they had been the victim of abuse.

A further 26% said that videos or photos of them had been uploaded online without their consent.

According to the poll, at least 27% of abuse came from parents, 64% were sent by pupils and 9% were sent by both.

The majority (58%) of teachers did not report abuse from pupils to their employer or police.

Nearly two thirds (64%) said that this was because they didn’t think anything could be done, 21% did not think it would be taken seriously, 9% were too embarrassed and 6% had previously reported incidents which had not been dealt with.

Where teachers did report abuse to their headteacher, 40% said that no action was taken against pupils and 55% said no action was taken against parents.

Where abuse was reported to the police, over three quarters (77%) said no action was taken against pupils and 76% said no action was taken against parents.

The overwhelming majority of comments were posted on Facebook by secondary school pupils.

General Secretary of the NASUWT, Chris Keates, said: “Technology has transformed the working and social lives of many teachers and enhanced the learning experiences of pupils.

“However, it is clear that steps need to be taken to protect teachers from the abuse of social media by pupils and parents.

“Teachers are often devastated by the vile nature of the abuse they are suffering.

“Teachers are often traumatised by the attacks made on them through social media.

“Some have lost their confidence to teach once they see foul and personal remarks made by pupils in their classes and have left the profession.”

Ms Keates said the government needed to do more in tackling the problem.

“Great strides had been made by the previous government, working in partnership with the NASUWT and other teacher unions and social media providers, in seeking to address this problem.”

She added: “Comprehensive guidance had been produced about social media and internet safety which promoted good practice for schools on how to protect staff, and indeed pupils, from abuse.

“One of the Coalition Government’s first acts was to remove the guidance on the grounds that it was unnecessary bureaucracy.

“Schools need policies which prevent abuse and identify sanctions which will be taken against parents and pupils who abuse staff in this way.

“Schools should also be supporting staff in securing the removal of the offensive material from social media sites and encouraging the staff concerned to go to the police.”