England's General Teaching Council found that Alison McGuire, who taught at Charles Dickens junior, Portsmouth, had put pupils' safety at risk. She also failed to follow proper procedures when pupils failed to return to school after lunch.
She must now take a course in teaching methods before returning to the profession and is banned from taking up a senior management post for three years.
Miss McGuire started at the school in January 1991 and was made deputy head in January 1999. The committee heard she had been an excellent teacher at a time when the school had five headteachers in five years, but her troubles began when she was off work for nearly five months from December 2002 after a close friend was killed in the Bali bombing.
She was given support on her return, but the school was concerned that it was not working. Her continued absences due to illness exacerbated the situation.
Sandra Miller, headteacher, said: "There was no one to deputise in my absence so I had to ask two members of staff if they would add deputising for me to their job description."
An incident in her class on July 1, 2003, led to her suspension. Miss Miller said pupils in Miss McGuire's class were found rolling around and another was cowering by the door having pencils thrown at her. She said:
"Later in the afternoon two pupils went missing and Miss McGuire failed to enter the proper records in the attendance registry."
Miss McGuire, who is not currently teaching, explained that she had been diagnosed with ME.
She said she hoped to work as a supply teacher when her confidence returned and wanted to move to Leicester to make a new start.