The use of the emergency alert to warn about wildfires is the most extensive use of the system to date, the Government said.

First Secretary of State Louise Haigh said: “In response to the continued risk proposed by wildfires, the government has taken the decision to issue an emergency alert to England and Wales. This is the most extensive use of the UK’s emergency alert system in response to an active incident, and reflects the seriousness with which the government is acting to safeguard people and property.

“During this period of extreme heat, we are asking people to take simple steps to limit the risk of further fires. By following the safety guidance, everyone can play their part in protecting local communities and supporting our frontline services who are working around the clock to keep people safe.

“The government will continue to provide every assistance to communities being impacted by these fires, including the deployment of 100 additional military personnel in major incident areas.”

Millions of people across England and Wales have just received an emergency alert on their phones warning against lighting anything that could spark a wildfire, including barbecues, campfires, and fireworks, the Cabinet Office said.

An East of England Ambulance Service spokesperson said they were called just after 2.10pm on Friday to the scene in Wickford and dispatched a “significant number of resources” to the scene, including a specialist Hazardous Area Response Team and critical care teams from charity partners including two air ambulances.

They said: “Our crews assessed 62 patients who were on board the train. Following assessment, all patients were discharged at the scene.

“We also assisted with the evacuation of a second train that was unable to continue its journey due to the derailment. There were no casualties among those on board.”

Investigations into two train derailments in two days “will look at all possible causes and factors”, a Network Rail boss said, adding the hot weather had “presented exceptional challenges to the railway”.

Martin Frobisher, Group Safety and Engineering Director at Network Rail, said: “We are currently responding to a derailment incident near Wickford station in Essex, and we are working quickly to understand the situation and to provide assistance where needed. Two carriages have derailed but remained fully upright, and there are no significant injuries reported.

“I appreciate the public will be concerned at the news of two derailments of passenger trains over a short period of time, but I want to reassure them that Britain’s railways still rank among the safest in the world, and that safety is always our first consideration on the railway.

“Our thoughts remain with everyone affected by yesterday’s significant incident at Lewes. I want to thank the teams from across the rail industry and emergency services who have been working around the clock to provide assistance and support to those who need it, as well as the response from the local community.

“The Rail Accident Investigation Branch is conducting an investigation into the derailment at Lewes, and has investigators on scene at the Wickford incident. We would ask people to avoid speculating on the cause of any incidents until further information is available. We will also conduct our own internal investigations, in which we will look at all possible causes and factors.”

Councillor Andy Barnes, leader of Basildon Council, said: “I would like to thank all of the emergency services who are currently responding to this incident. Our thoughts are with everyone affected, and we sincerely hope that all those involved are safe and well.

“Basildon Council will continue to support our emergency service partners in any way we can as they carry out their response.”

Basildon Borough Council has said that there were around 40 to 45 passengers onboard the train when it derailed near Wickford this afternoon.

It was travelling from Southend towards London and "no major injuries have been reported", according to the local authority.

"Council officers are also at the scene and are liaising with partner agencies," a spokesman says.

"The council is in contact with emergency services and other partners and is providing support as required."

They said that an air ambulance landed at the scene as a precaution.

The DfT has released a statement following the derailment this afternoon.

A spokesperson said: “We are aware of a derailment involving a Greater Anglia train near Wickford, Essex. The train is upright, there are no reported injuries and investigators have already been deployed to the site.

“Our railways remain amongst the safest in the world and while incidents like this are extremely rare, when they do occur, they are taken very seriously.”

The Rail Accident Investigation Branch (RAIB) have sent inspectors to the incident near Wickford.

The organisation posted on X: "RAIB has deployed a team of inspectors to the site of a passenger train derailment at Wickford, Essex to begin gathering evidence."

Passengers are facing major delays to their journey after the derailment.

National Rail have confirmed that trains operating between London Liverpool Street and Southend Victoria are being cancelled in full.

Customers have been advised to use alternative services, and have been told that the Southminster branch line is also affected by this issue, with services currently also unable to run between Wickford and Southminster.

The major disruption is expected to continue until further notice.

Greater Anglia said: “If you have already started your journey, please speak to a member of staff or use a help point for assistance on completing your journey.

“We are gathering reports of reports of an incident between Southend Victoria and Wickford. We are currently awaiting further details and will provide updates as soon as possible.”