One person has died after two trains collided in Bedford, according to British Transport Police
A major incident has been declared, with firefighters, police and ambulance crews at the scene
The trains involved were the 16:40 from Corby to London St Pancras and the 15:50 from Nottingham to London St Pancras
Passenger Peter Knapp tells BBC News he was in the front carriage of one of the trains: "I felt like I'd been in a bomb explosion"
"It was like a big bang, then people flew from their seats," says passenger Shola Mene
East Midlands Railway says all its services to and from London St Pancras have been suspended for the rest of the day
Rail operator Thameslink says all lines are blocked between Luton and Bedford and is urging people not to travel
Image source, Katy Lewis/BBCTrain information screens at St Albans railway station show services that are affected.
St Albans is south of Luton. Bedford is further north of Luton on the same line.
Image source, Dr Peter KnappBBC reporter Holly Nichols is in Bedford near the scene of the crash."I can see about 30-40 people walking towards us. There are lots of very upset people," she says.
"It is mostly commuters, but a mix of ages.
"Family members are turning up to pick people up," she added.
She could also see police vehicles and a cordon at the site.
Passenger Peter Knapp tells BBC News he was in the front carriage of one of the trains involved in the collision.
"I felt like I'd been in a bomb explosion," he says.
He describes seeing "bloodied faces", people with what appeared to be broken legs, and "smoke everywhere".
Knapp says he "can't sit down because my back hurts so much” but is otherwise "OK".
He says he "must have been very lucky" but "can't imagine what the situation of the driver is".
Knapp is now on the main road "parallel to the train" and describes seeing ambulances, fire engines and police at the scene.
East Midlands Railway services to and from London St Pancras are suspended for the remainder of Friday, the train operator has said following a collision between two passenger trains in Bedfordshire.
Transport Secretary Heidi Alexander says she is "deeply concerned to hear reports of the collision involving two East Midlands Railway passenger trains".
"I’m grateful to emergency services who are on the scene, attending to those affected. We're working quickly with the rail industry and local partners to support passengers," she adds in a post on X.
Image source, Dr Peter KnappThe East of England Ambulance Service has sent "a number of resources" to the scene including an air ambulance, a spokesperson said.
The air ambulance has been spotted on Flightradar24 flying in the area south of Bedford.
A Hazardous Area Response Team has also been sent by the ambulance service and it encouraged people to avoid the area.
Bedfordshire Police has said in a social media post, external that officers are also at the scene of an incident on the railway line, just south of Bedford.
"All lines through the area have been stopped," a spokesperson said.
"Please check your journey before you travel and allow plenty of extra time.
"We are asking people to avoid the area and we will update when we can."
Operator East Midlands Railway says its services are also being affected by the incident.
Trains between London St Pancras and Leicester are being disrupted and are unable to run in or out of London "for the remainder of this evening".
"Passengers are advised not to travel," it said.
British Transport Police is responding to reports of a “collision involving two trains” in the Bedford area, the force says in a statement on social media.
Thameslink reports that all lines are blocked between Luton and Bedford and have been since about 17:30 BST.
Numerous services this evening have been delayed and will likely be cancelled due to the ongoing incident.
Those currently on trains along the line have been told by the rail operator to remain on board and await further information.
A spokesperson for Thameslink told the BBC the emergency services were dealing with an incident and they directed further inquiries to the British Transport Police.
Bedfordshire Fire and Rescue Service has confirmed on social media that it is at the scene of the incident on the railway just south of Bedford.
"Please avoid the area," a spokesperson says.
A spokesperson for rail operator Thameslink is "strongly" urging people not to travel until later today.
"If you cannot delay your journey, please note that you will be severely delayed and will likely need to use an alternative route to reach your destination."
Replacement buses have been requested, they added.
Thameslink says all lines are blocked between Luton and Bedford due to a "problem under investigation"