Police were called out after a man received a toxic liquid burn on his back at Chafford Hundred Rail station yesterday.

British Transport Police first tweeted the incident yesterday at 3pm, describing the burn as taking place outside the station in “unknown circumstances.”

Essex Ambulance said the burns were minor and the man, “in his late teens”, did not need to be taken to hospital.

A BTP spokesman today said the burn had come from a toxic substance in the man’s backpack and they were investigating how the substance had got into his bag.

The spokesman said: “A man reported burns to his back from his back pack. The burns proved to be from a toxic substance in his bag.

“We are working to establish what happened. We are not clear on where the substance came from.”

Police enquiries are continuing into the mysterious incident.

Essex Ambulance said: “We were called out to Chafford Hundred rail station yesterday at 3.19pm and treated a man in his late teens for a minor injury described as a burn to his back."

They added the man had been treated and discharged at the scene.