John Ellis
John Ellis was a citizen of the United Kingdom from 1953 who accidentally, with Diane Holmes and Emma-Louise Cowell, came through the Cardiff rift, travelling more than fifty years into the future.
He was a fireman during World War II but worked in retail in 1953. He was supposed to finalise a deal in Dublin on 19 December, the day after he disappeared.
After arriving, John saw his by then elderly son Alan, who suffered from Alzheimer's disease and failed to recognise him. Alan had married a woman named Sally but they had no children. John saw no purpose in his life now that his family was gone.
He tried to commit suicide but Jack Harkness stopped him. After explaining himself, Jack decided to let him kill himself. He did so by carbon monoxide poisoning, sitting alongside Jack and holding his hand till his last breath (TV: Out of Time)