A teenage rugby player fell to his death from a fourth-storey window because he was sleepwalking, an inquest has concluded.

Ross Kimpton, 17, was visiting Britain from New Zealand on a rugby tour. He stumbled through an open hotel window 15m (50ft) above the ground after drinking with his friends.

His alcohol intake, which was described as being more than twice the level permitted under British drink-driving laws, probably contributed to his death, the coroner said.

The teenager walked through a large sash window and fell to the pavement below his room in the London Lodge Hotel in Paddington, West London. He was dead within seconds.

Alcohol, along with jetlag and being in a foreign country, put him at risk of sleepwalking, and he had suffered from the condition as a child, the inquest at Westminster Coroner’s Court was told.

Irshaad Ebrahim, a consultant working at the London Sleep Centre in Harley Street, said that alcohol was a likely “priming factor” for sleepwalking. “If there is a precipitating event, something such as a loud bang, someone snoring in the room that disturbs someone in deep sleep, that could precipitate a sleepwalking episode,” he said.

“The window was open and there could have been a loud noise coming from outside. He was in a strange environment, in a different bed in one of the busiest cities in the world. These are factors in sleepwalking.”

Ross’s teacher, Brett Rossoman, who described the teenager as being one of his favourite pupils, said that he rushed out of the hotel after he heard a thud outside at 1.15am. Mr Rossoman found the boy dead in a pool of blood. “Two of us ran outside,” he said. “We found him face down. I took a pulse on his wrist and his neck, but I could not find a pulse. There was no breathing.”

Ross’s parents, Murray and Theresa, flew to London from their home in Auckland, to hear the coroner, Paul Knapman, record a verdict of death by misadventure.

Mr Kimpton said in a statement read to the inquest that Ross had been looking forward to the trip. “Ross was very keen on rugby and he held fundraising events to obtain the money,” he said. “There is no doubt that Ross was happy and pleased to be going on the trip and he had been talking about it a great deal for months.”

Mr Kimpton said that Ross used to sleepwalk when he was younger, but thought he had grown out of it.

Mr Rossoman recalled that earlier in the evening he had given the boys £10 each to buy their dinner and told them not to drink alcohol. He went to check that the boys had returned to their rooms at 10pm and found that most of his pupils were in Ross’s room drinking.

“There were up to 16 of them in his room. I saw four cans of beer, one on a wardrobe and three others in the hands of boys. Straight away I gave them a warning. I dealt with them quite severely and told them to go to bed. It is my belief that they went to sleep after that.” Photographs of the room taken after the tragedy showed a bin in the room full of empty beer cans.

Mr Rossoman said: “He was one of my favourite students. I knew him very well. From what I hear he was not naive as far as alcohol is involved. He used to drink socially.”

Victoria Stead, a paramedic who was called to the scene, said that she found Ross lying on his back with two men attempting to revive him.

“He smelt of alcohol and he was wearing a top, boxer shorts and socks,” she said. “The hotel sign behind looked like it had been hit by the patient. He had obvious severe facial and head injuries. He was unresponsive and not breathing.” She pronounced him dead at the scene.

A postmortem examination found Ross had a blood-alcohol level of 179mg per 100ml, 2¼ times the drink-drive limit. The base of his skull was fractured in three places and his lungs had been flooded with partially digested food, the result of reflexes caused by a traumatic head injury.

Ross would have died in seconds and could not have been saved outside a hospital, the inquest was told.

Police investigating the death did not suspect murder or suicide and did not believe Ross had climbed out of the window as a prank while drunk. The coroner said that he did not believe the death was a result of “drunken partying” but that alcohol had been a factor in the death. “It is highly likely that this was a form of sleepwalking,” he said. “You can imagine the shock and tragedy and horror [for Mr Rossoman] of finding one of his boys in the street outside.

“To have a group of rugby-playing New Zealand adolescents staying in the West End of London, I do not think underage drinking should be condoned but quite frankly I would be astonished if some of these boys had not tried to go drinking.”