A primary school headteacher has warned parents about children using social media after hearing “inappropriate language” in her classrooms.

Kerry Jones has written to parents of children at Phoenix Primary School, Laindon, asking them to monitor youngsters’ online activity.

The head is worried about pupils using mobile phones, tablets and computers to visit unsuitable websites.

Mrs Jones makes her plea in the latest school newsletter sent out to parents.

She said: “It has been noted some children are using inappropriate language in school.

“Please ensure you speak with your children and have the adequate safety filters in place to protect your children from inappropriate downloads on social media sites. Please be reminded mobile phones can be used to access these sites.

“Parents will be contacted directly if we have any concerns regarding their child.”

One of the world’s most popular social media websites, Facebook, insists users must be at least 13 to register for an account, but such a rule can be hard to enforce.

Jerry Glazier, Essex general secretary for the National Union of Teachers backedMrs Jones’s view.

He said: “Primary school-age children should not be on Facebook.

“The plethora of social media is a nightmare for parents, but their responsibility is to know what children are using.

“It needs to be appropriate and parents need to make sure they are not enabling their kids to access inappropriate sites.

“It is their responsibility to safeguard their children and schools are continuing to remind parents of that.

“You are not supposed to have a Facebook account at that age and if a parent is aware their child has an account, it is a breach of the regulations.

“Keeping children safe must be a prominent concern for schools and parents.”

Last year, Robert Harris, the new headteacher of the FitzWimarc School, in Hockley, Road, Rayleigh, barred the use of the word “banter” to describe pupils’ bad behaviour.

Phoenix Primary School refused to comment further on the head’s message to parents.