Southern Rail service from London Victoria to Eastbourne leaves tracks near Lewes, prompting major emergency response as 18 passengers hospitalized.

Eighteen people were injured—two seriously—after a passenger train derailed near Lewes in East Sussex, southern England, prompting a major emergency response.

The Southern Rail service, traveling from London Victoria to Eastbourne, was carrying approximately 150 passengers when its last three carriages left the tracks and toppled onto their sides. Emergency crews rescued and evacuated all passengers, while 16 people with less serious injuries were taken to hospital.

British Transport Police declared a major incident as police, firefighters, and ambulance crews responded to the crash. Passengers who did not require hospital treatment were taken to a nearby community centre for support, and authorities urged the public to avoid the area.

The cause of the derailment remains unknown.

The Rail Accident Investigation Branch has deployed inspectors to examine the scene, while Network Rail said the railway between Haywards Heath and Lewes would remain closed for some time as specialist teams assess the damage.

The derailment occurred amid a heatwave in southern England, where temperatures reached about 35°C (95°F). Rail authorities had already imposed speed restrictions and canceled some services because of the heat, which can cause tracks to expand and buckle—although officials have not linked the derailment to the weather.

Meanwhile, Transport Secretary Heidi Alexander expressed concern over the incident and thanked emergency responders. Southern Rail advised passengers not to travel through Lewes as emergency and railway teams continue their work at the scene.