He said Mr Gilmer left the compartment, but then minutes later, as he read through documents for an inquest he was attending the next day, felt his head being pushed back against the seat headrest, while something was pushed into his mouth.

He told the court: “ "I felt an object being pushed into my mouth. I smelt stale alcohol. The defendant's speech was not coherent but he said 'eat this you ****'."

Mr Ellis, who is head of clinical negligence and personal injury at his London chambers, spat out the object and discovered it was a tightly folded £10 note.

Mr Gilmer was spoken to by police when the train arrived at St David’s Station, Exeter but claimed he had simply been trying to pay for the items he had taken.