A Thai ‘teacher from hell' left a 15-year-old boy with crippling injuries after punishing him with 200 jump squats.

Strict 'Miss' Khun Rattanakorn, 31, imposed the harsh discipline on the high school student when he was caught skipping classes in Kanchanaburi province on July 23.

She proceeded with class but the youngster complained that the back of his knee was painful so she took him to the hospital.

The school nurse could not diagnose what was wrong with the boy so they rushed him to the Lao Kwan Hospital where a doctor confirmed he suffered myofascial pain syndrome that required surgery.

Furious mother Lek Au-Thong, 59, said: ‘My son missed more than a month of schooling and is still struggling to walk. I really believe that the disease was a result of the teacher's punishment.'

The first operation happened on August 8 followed by a second on August 24. He also had an infection on his knee which made the injury worse.

The working mom initially agreed with the school administrators that the incident would be kept secret as long as they compensate his son for their expenses.

However, the teacher could only afford 30,000 baht to give to her so she came out to the media to seek help.

She said: ‘I already agreed to reduce the compensation to 150,000 baht from 250,000 baht. My son could not walk so I had to stay home and take care of him. It's not enough.'

Thai Ministry of Education allows teachers to punish students by admonishing, ordering to attend activities, or doing training. However, teachers who 'cause bodily harm' can be jailed for up to ten years if found guilty.

The school board and the boy's parents will arrange another meeting to discuss the incident sometime this week. His parents say they want compensation to cover his medical costs.