A total of 20 children and 10 adults were on board the 71-seater coach when a nine-year-old boy fell from the vehicle on the A47 near King's Lynn this afternoon
The youngsters are from Stamford Rugby Club in Lincolnshire and were travelling home after playing in a tournament at Holt in north Norfolk when the incident happened.
Superintendent Dave Marshall said:
This is a serious incident which has left a nine-year-old boy fighting for his life.
The circumstances of how the boy came to fall from the coach will form part of our investigation and it would be inappropriate to speculate further at this stage.
The boy's parents, who were travelling with the teams, are being supported by specially trained officers.
A nine-year-old boy is in hospital with "life-threatening injuries" after falling from a coach this afternoon, police have said.Officers in Norfolk said nobody else was injured in the incident, which happened at around 3.45pm on the A47 trunk road near King's Lynn.
A police spokesman said: "The boy has been taken to the Queen Elizabeth Hospital in King's Lynn with life-threatening injuries.
"A number of other people were on board the coach at the time and no other passengers were injured."
The road is expected to remain closed for some time and local diversions have been put in place.Anyone with information is asked to contact police.
An investigation into the helicopter crash in which Conservative peer Lord Ballyedmond and three others died in Norfolk has not yet identified any technical malfunction that might have caused the accident, a special bulletin from the Air Accidents Investigation Branch has said.
Air quality monitoring stations across the UK measure particles of dust in the air that can be breathed into the lungs.
ITV News Correspondent Rupert Evelyn visited a monitoring station in King's Lynn in Norfolk:
Health manager Dave Robson of King's Lynn and West Norfolk Council told ITV News the levels at the local station were "above what we'd normally see".
Investigators poring over the wreckage of the helicopter crash which killed Conservative peer Lord Ballyedmond and three others have begun recovering debris from the wreckage.
Two pilots killed in the crash in Norfolk were named as Carl Dickerson, chief pilot at Haughey Air Ltd, and Lee Hoyle, a co-pilot at the company, which was owned by the Tory entrepreneur who was one of the richest men in Northern Ireland.
The fourth man who died was named locally as Declan Small, 42, a foreman who worked for Lord Ballyedmond. He came from Mayobridge, Co Down.
Tory peer Lord Ballyedmond was among four killed after a helicopter crashed in Beccles.Read the full story ›
David Cameron said in a statement:
Lord Ballyedmond was a towering figure in Northern Irish business life, and passionate about peace and good relations north and south, east and west.
He was a larger than life figure who was a great supporter of the Conservative party and a good friend to me.
Those killed in the helicopter crash in Norfolk have been named by the Norbrook Group. Lord Ballyedmond, who was killed in the crash, was the founding member of the pharmaceutical company.
The statement reads:
"Norbrook management and staff also mourn the loss of their friends and colleagues Declan Small (Site Foreman), Captain Carl Dickerson (Pilot) and Captain Lee Hoyle (Pilot).
Our thoughts are with the immediate families and friends of the deceased who have requested privacy at this difficult time."
The helicopter that crashed in Norfolk last night, killing four people, took off from the stately home Gillingham Hall, police confirmed.
The property was owned by Conservative peer Lord Ballyedmond, who was among the four men killed in the crash.
Norfolk Police added that a "significant cordon" remained in place around the site of the crash.
Conservative peer Lord Ballyedmond, who was among four people killed in a helicopter crash in Norfolk, had previously raised safety concerns with the aircraft's manufacturers.
AgustaWestland said they were investigating but that "there could be many causes" behind last night's crash.