Illegal cigarettes are being sold under the counter to Spalding students at a local shop.
That is the concern of a headteacher after a teenager was caught with two packets of cheap Pall Mall blue cigarettes.
The incident at Sir John Gleed School was investigated by PCSO Paul Coupland during the live Twitter Patrol with the Lincolnshire Free Press on Friday.
PCSO Coupland was called to the school to talk to the youth, who had paid £5 for two packets of cigarettes.
He said: “At that price the chances are these cigarettes are illegal and they will now be handed over to Trading Standards.
“Smoking at schools is nothing new, but what students don’t realise is if they sell cigarettes on and the person has an allergic reaction to them, they will be the first port of call if anything happens.”
Headteacher Janet Daniels is keen to make a plea to local shops not to sell cigarettes to her students.
She said: “At this time we are not sure whether there is an adult involved in buying the cigarettes for students, but we would like to make a plea to local shops not to sell cigarettes to our students.
“We work very hard at this school and within our sports departments to promote a healthy lifestyle for our students.
“Our Rock Challenge project shows them you can have fun without the use of smoking, drinking or illegal substances.”
Insp Jim Tyner said: “This is a perennial issue that has been going on since before I was a schoolboy. We will be working with the schools and with Trading Standards to make it as difficult as possible for pupils to obtain cigarettes.
“I would urge parents to be alert and take appropriate action if they suspect their children are smoking.”