A Teesside schoolboy, awarded damages after being hit in the face with a golf club during a PE lesson, has been stripped of his £21,000 payout.
Sam Hammersley-Gonsalves was 11 when his teeth were smashed and jaw broken during a golf lesson at Guisborough's Lawrence Jackson School in 2007.
His family successfully sued Redcar and Cleveland Council, claiming his teacher failed to properly supervise the class.
But after the authority appealed, judges overturned the decision.
The youngster, now 16, was hit in the face by a fellow pupil during the lesson in October 2007.
The family was awarded damages at a hearing at Middlesbrough County Court in November last year, which ruled the teacher in charge had been negligent in failing to keep every pupil in the class of 22 "in his line of sight" at all times.
But the council appealed against the ruling, arguing the decision placed "an unrealistic burden" on schools and teachers.
At an Appeal Court hearing in London, Lord Justice Pill, sitting with Lord Justice Rimer and Lady Justice Black, said that teachers "cannot be expected to see every action of every pupil" in their care.
Sam's parents Kim and Tom, from Guisborough, plan to take the case to the European Court, claiming they need £35,000 to cover medical and dental bills.
Mr Hammersley-Gonsalves said: "This is all purely to cover the costs of the work that he needs to repair his teeth.
"He will lose six teeth, four of which are already dead and need replacing, but he can't have that done until he is 18. A further two are almost dead and also have to be replaced."
So far, Sam has had dental work covered by the NHS because of his age. But he is unable to have dental implants to replace his severely damaged teeth until he is 18.
Welcoming the ruling, Redcar and Cleveland Council said it showed that sport was encouraged in schools, but that "accidents will happen".