Two passenger trains collided in Britain on Friday evening, killing at least one person and injuring dozens more, according to the authorities.

The collision took place about 5:15 p.m. local time near the town of Bedford, in south-central England, officials said, prompting a major emergency response from the police and health workers, according to the transport police.

The East England Ambulance Service said in a statement that one person had died at the site of the crash. Eleven others suffered life-threatening injuries; 22 people, less gravely hurt, required immediate treatment; and 56 others had minor injuries, the statement said.

In a statement published shortly later, Britain’s transit workers’ union said that a driver of one of the trains, a former union representative, had died.

An operator at Bedford Hospital said by phone that the medical center was preparing for a “major incident” after the collision. The East England Ambulance Service also said it had sent an air ambulance to the scene, and encouraged people to avoid the area. The town is about 45 miles north of London.

“It felt like a bomb, like I was in an explosion,” Peter Knapp, a 40-year-old air quality scientist and a filmmaker, said of the crash. He was in the front carriage of the train that rammed into the one ahead of it, he said, adding, “I’m amazed that I’m walking and breathing.”

Mr. Knapp said that afterward the carriage was full of dust, with the train’s seats “all over the place.” He said that some people’s faces were covered in blood, and that he saw at least two people with what he called life-threatening injuries. He himself was bleeding from his shins and in a wheelchair after the crash, which he said caused his back to seize up.

The British prime minister, Keir Starmer, said that reports of the collision were “hugely concerning” and that his thoughts were with the family of the person who had died and with the others injured.

The trains that collided had been headed to London St. Pancras, one of England’s busiest train stations. They departed for their destinations about an hour apart, according to the East Midlands Railway, a British train operating company.

Officials from the Rail Accident Investigation Branch said that a team was on site to gather evidence about how the collision happened.

Michael D. Shear contributed reporting.