A woman who e-mailed a school to complain about its unruly pupils received a letter from the headmaster saying "tell her to get stuffed".
Mary Kelly, 62, from Marlborough in Wiltshire, sent a note to the bursar of St John's School after pupils climbed over her fence into her garden.
Her letter was forwarded to headmaster Patrick Hazlewood who sent the reply thinking it was going to the bursar.
Mr Hazelwood has since apologised for his remarks.
Mrs Kelly, who has forgiven the mistake, said: "I was a bit shocked but, to be fair, he did not mean to send it to me."
She said she has not had any further trouble with the pupils.