Mum was right: Never stick your head out of a moving train... or this happens

A man in his 20s met a gruesome end by reportedly being decapitated after sticking his head out of the window of a Gatwick Express train in London.

Eyewitnesses told Wandsworth Radio that his head “flew off” after being hit by another train, but others claimed he was struck by the embankment with no other vehicle involved. Authorities have said only that the unfortunate young man suffered a fatal “blow” to his head.

Two women on the platform and up to 20 people inside the train, including at least one child, saw the gruesome moment happen.

“He lifted his head out and didn’t notice that the train was coming, so all you see is basically a head gone,” Rianna from Battersea told Wandsworth Radio. “The head flew off. I actually ran because it was disgusting but all I saw was just a head flew away.”

Police, ambulance crews, and helicopters responded to the incident at Wandsworth Common station, with shocked passengers said to be screaming as they got off the train.

“We treated a person at the scene for a head injury, but sadly they were pronounced dead by the doctor from the air ambulance,” a spokesperson for London Ambulance Service said.

Twitter users were baffled by the incident as the windows on the Gatwick Express train do not open.

Some users claimed the model being used was an older version of the train which has large windows that can be opened.

A statement from the British Transport Police claimed he was leaning out a train door window and was not decapitated, despite the accounts from eyewitnesses, but rather “suffered a blow to the head.”