Emergency services were called at about 5:15 p.m. (1615 GMT) to the line south of Bedford, where two East Midlands Railway trains were involved in the crash.
A video posted on social media by one of the passengers showed what appeared to be the front of one train entangled with the back of another, with the carriages appearing to remain upright on the tracks.
“My thoughts are with the family of the person who has sadly lost their life, and with those who have been seriously injured,” Prime Minister Keir Starmer said in a statement.
The East of England Ambulance Service said a large number of crews had been deployed, including more than 20 ambulances and six air ambulances.
One person died at the scene, 11 people suffered very serious injuries, 22 were seriously injured and 56 had minor injuries, it said.
Deputy Chief Constable Stuart Cundy said a significant emergency service response was under way as authorities worked to establish what had happened.
Peter Knapp, a doctor who said on social media site Bluesky he was on board one of the trains, described a “sudden crash” with one carriage off the rails and said he had sustained minor injuries. (Reuters)
