Emergency services are at the scene of a train derailment between Haywards Heath and Lewes in Sussex.
Photographs shared online show at least two carriages of a train lying on their side, with two passengers stood on top.
In a statement, British Transport Police said: “Officers are currently on scene close to Lewes railway station following reports of a derailed train at 3.54pm today (13 August).
“We’re responding alongside paramedics and the fire service and will provide more information as soon as we can.”
In updates, Southern Rail said passengers who are currently on trains close to Lewes station should remain on the train and await further updates.
The rail operator said: “Emergency services are making their way to the scene and we are working out the impact this will have on our network.”
Transport secretary Heidi Alexander said she is “deeply concerned”. She added: “Grateful to emergency services who are on the scene supporting those impacted.“We are working quickly with the rail industry and local partners to assist passengers.”
Have you witnessed the crash or have pictures from the scene? Email bryony.gooch@independent.co.uk
Pictured: Where the track bends as train derails near Lewes
Ambulance service sent 'resources' to the scene
South East Coast Ambulance Service (SECAmb) said it sent resources to the scene of the derailment after being alerted just before 4pm.
A spokesman said: “South East Coast Ambulance Service is currently responding to reports of an incident near Lewes railway station in Sussex.
“We were called shortly before 4pm and have a number of ambulance resources at the scene, including specialist teams, working alongside our emergency service partners.
“We have no further information to share at this time but will provide updates as soon as possible.”
Pictured: Derailed carriages seen from above as emergency services free passengers
'No serious injuries or fatalities - report
A source from the Department for Transport told the BBC that the latest understanding is that there are "no serious injuries or fatalities".
This remains a developing incident and The Independent will bring you the latest.
Pictured: Photo from the carriage as train is derailed
Local MP describes incident as 'serious and developing'
The derailment was described as “a very serious and developing incident” by a local MP.
James MacCleary, the MP for Lewes, wrote in a Facebook post: “I am aware of very concerning reports of a train crash in the Lewes area this afternoon.
“I am in touch with the relevant authorities now and will provide further updates as soon as I have more information.
“This is clearly a very serious and developing incident, and my thoughts are with everyone affected.
“In the meantime, if you are concerned about someone or need urgent assistance, please contact the emergency services.”
Too early to estimate number of injuries, says ambulance service
South East Coast Ambulance Service has said it is too early to estimate numbers injured but they were at the scene "with a number of resources" including ambulances, operational managers and critical care paramedics.
A spokesman said as soon as they knew numbers, they would release the information.
Passenger wellbeing must be prioritised, says union boss
The general secretary of a transport trade union has said “with so many passengers reportedly involved” in a derailment near Lewes, “the immediate priority must be their safety and wellbeing”.
Maryam Eslamdoust, general secretary of the TSSA (The Transport Salaried Staffs’ Association), said: “We are deeply concerned by today’s derailment and our thoughts are with the passengers, emergency services and rail workers affected.
“With so many passengers reportedly involved, the immediate priority must be their safety and wellbeing.
“We thank the emergency services, British Transport Police and Southern Rail staff responding at the scene.”
Pictured: Passengers stand on top of two derailed carriages
Photographs shared on social media have shown at least two carriages of a train lying on their side, after reports of a train derailment in Sussex.
The pictures on X showed passengers standing on the top of the carriages, with emergency service vehicles and staff around the scene.
Derailment 'deeply distressing', Labour MP says
Helena Dollimore, the Labour MP for Hastings and Rye in East Sussex, said news of a derailment in the area was “deeply distressing”.
She said: “It is deeply distressing to hear that a train on our local line has derailed near Lewes.
“I have spoken with the secretary of state for Transport (Heidi Alexander) and the rail minister (Lord Hendy of Richmond Hill) who are keeping me updated on the situation.
“I know many people locally will be concerned, and the thoughts of everyone are with those affected and the emergency services responding at the scene.”
Ms Dollimore urged her constituents to contact her office if they need “urgent support”.