A knife disguised as a highlighter turned up in a 12-year-old student’s backpack in England — prompting school officials to investigate as the country grapples with a surge in deadly knife crime.

The little girl was “hysterical” after finding the small blade in the tip of a green highlighter at the Boldon School in South Tyneside on Thursday, a family member told the Sun.

A school spokesperson said they were alerted of the discovery through social media and “immediately carried out a thorough investigation,” which included talking to students and conducting random, voluntary bag searches.

“We appreciate tensions are running high with knife crime on the agenda at a national level,” the spokesperson said. “We will deal with any pupils found to be involved in this type of activity in the appropriate manner. This is something we take extremely seriously and would urge any parents or members of the public who have any concerns or information to contact the school direct.”

The girl’s relative denied that the doctored highlighter belonged to her.

“She said someone had put it in her bag. She hates anything like this and I was shocked that someone would do this,” the relative said. “It’s ridiculous people are making things like this. It could cause someone serious harm.”

So far this year, 42 people have been stabbed to death across the United Kingdom, with 17 in London.

But recent statistics show knife crime is rising in counties outside of the capital — by an average of 44.8 percent over the past eight years, according to the Guardian.