Parents who hire bouncy castles for a child and his or her friends could be liable for damages for any injuries suffered by the children after a landmark High Court ruling yesterday.

A teenager who was brain-damaged when he was kicked in the head on a bouncy castle won a damages action yesterday against the couple who hired it for their child’s birthday party. The High Court ruling paves the way for further claims against parents and companies who fail to supervise children playing on inflatable toys.

Sam Harris, then 11, was hurt when a much taller and heavier 15-year-old fell on him as they were somersaulting on the castle in September 2006.

He fractured his skull, causing “serious and traumatic brain injury”. Sam, who has Asberger’s syndrome, now needs round-the-clock care, his solicitor said. She added that the amount of damages, which will be assessed at a later trial, was likely “easily” to exceed £1 million.

Sam brought the case through his mother, Janet Harris, of Spalding, Lincolnshire, against Catherine and Timothy Perry, who hired the castle for their triplets’ tenth birthday party. He had climbed on to the inflatable after leaving his father, who was playing football with him in an adjoining field, after asking Mrs Perry’s permission.

He and a friend started doing somersaults, prompting the older boy, who was described in court as a “gentle giant” and an “enormously tall boy”, to try the same. As he did so, his heel struck Sam hard on the forehead.

The Perrys denied liability and blamed Sam’s father, David, who was joined as a third defendant and accused of failing to supervise his son. Mr Justice David Steel ruled that the Perrys, who were insured, were liable and dismissed the case against Mr Harris.

He found that Mrs Perry had given Sam permission to use the castle and had failed to watch him properly.

At the time of the accident, she had been strapping another child into a second inflatable, a bungee run, and had her back to the castle, the judge found. “Both pieces of equipment needed uninterrupted supervision,” he said.

Mr Justice Steel said that Mrs Perry should have been there to stop the boys as soon as one of them “tried a flip”. He added that Mrs Perry had also failed negligently to ensure that all the boys on the castle were of the same size.

Instructions provided with the castle had warned the Perrys not to allow “somersaults and rough play” and not to “mix children of different sizes”.

The judge said that the allegation by the Perrys that Sam’s Asperger’s syndrome meant that he needed greater supervision was withdrawn during the trial and “should not have been made in the first place”.

He added: “It had no materiality and wholly failed and, in my judgment, was an unattractive allegation to make.”

Without that allegation, the residue of the case against Mr Harris was left “in some disarray”, he said.

However, he gave the Perrys permission to appeal because of the ruling’s “potential significance”, not just to the couple, but also to those who operate inflatable equipment.

He said that if the appeal was not pursued, Sam should receive an interim payment of £100,000.

After the hearing, Mr and Mrs Harris said in a statement: “Our sole motivation for pursuing this claim was, and has remained throughout, to obtain damages for our son Sam who suffered a very serious injury in this accident.

“We are both very relieved that the court has found that Mr and Mrs Perry were negligent as this will now enable us to obtain the specialist support and treatment that Sam needs.”

They added: “While we never wanted the case to conclude at trial, we are pleased that this has provided an opportunity to highlight just how dangerous bouncy castles can be if they are not supervised properly.

“We appreciate that thousands of children enjoy playing on bouncy castles every year, and we would not wish to stop that happening, but it is vital that those hiring them supervise them properly if accidents like Sam’s are to be avoided.

“The injury that Sam has suffered has and will continue to have a profound effect upon his life. The damages he will receive will hopefully help to improve his quality of life and we hope that the publicity that this case has received will help to prevent other children and families suffering as Sam and his family have.”

A recent government survey estimated that bouncy castles caused between 2,500 and 3,000 injuries each year. In 2006, two women in Co Durham fell to their deaths when a giant inflatable maze, designed by the artist Maurice Agis, tore free of its moorings in high winds.

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