Another 28 people were injured, four seriously, and all were children aged between 14 and 18, said a Cologne police spokesman. The dead are believed to be an assistant driver seated at the front of one of the buses. and a 14-year-old boy.

Today is the beginning of the half-term break for many British schools and the children came from Norfolk and Suffolk in East Anglia.

The accident happened at 5.45am local time on the A4 motorway between Kerpen Buir and Duren, southwest of Cologne, where the weather was cloudy but dry.

A lorry was also involved in the incident. It is believed the lorry crashed into one of the coaches, which had stopped on the motorway hard shoulder. The second bus then crashed into the scene.

Emergency services closed the motorway as they picked through the wreckage. Children were treated on the grass verge while others were taken to hospitals.

Andreas Moh, from Cologne Police, said the children were taken to makeshift first-aid centres at a school and fire station in Kerpen.

"The children have been traumatised and distressed, " he said. "They are heading back to Britain today. The teachers are with them but none of the teachers was hurt.

We are at the scene and obviously we are still investigating what has happened."

One of the coaches was carrying students from Thomas Mills High School in Framlingham, near Ipswich.

Francis Thomas, of Suffolk County Council, said the children were on their way to a skiing holiday in Austria.He said he could not confirm or deny whether the dead teenager was a pupil at the school.

He said it was half-term in Suffolk and many parents had gone on holiday as well, making it more difficult to contact them. He added: "We are in touch with British consulate officials at the scene and we are trying to contact parents as quickly as possible."

Thomas Mills High School is a rural community technology college, teaching pupils aged between 11 and 18.

The second coach, owned by Ambassador Travel, was carrying teenagers from Norwich School, an independent boys' school in the city. A county council spokesman said none of the children was seriously hurt on the Norfolk bus.

"We believe all the pupils from that school are uninjured, " he said. "They are being brought home at the moment.

The school is a private school and so they are making arrangements, but we are supporting the school directly."

Mike Pleasants, assistant operations manager for Ambassador Travel, said the coach left the UK on Friday.

The British Foreign Office said a group of 10 specialists trained in dealing with trauma and disasters were on their way to Germany from London. The rapid deployment team will be joined by a small party from International SOS, which provides medical assistance around the world.

Local police said the motorway branch of the service would be responsible for the investigation into the crash.

Jim Hawkins, head teacher of Norwich School, said 36 pupils and five teachers from the school were involved in the crash.

They had been on a weeklong skiing trip to Austria and were "caught up in a crash that happened in front of them", he added.