Billy Shipton

DCI Billy Shipton was a police detective working in London during the early 21st century, who later became involved in the video production industry in the late 20th century.

Investigations
Stationed in London, in circa 2005 Shipton began investigating the disappearance of multiple individuals near an abandoned estate called Wester Drumlins. Eventually, anyone who reported someone missing in the vicinity would be automatically referred to Shipton. During Shipton's investigations, numerous automobiles were impounded, their occupants missing. Dubbed the "Wester Drumlins Collection", by 2007 the impounded vehicles even included a 1960s-era police box, although Shipton was familiar enough with these obsolete objects to identify some errors in its construction.

Meeting Sally Sparrow
In 2007, Shipton's investigations leads him into contact with Sally Sparrow, who is herself investigating the disappearance of her friend Kathy Nightingale from Wester Drumlins. Sally and Billy immediately hit it off, with Shipton giving her the nickname "Gorgeous Girl" and convincing her to give him her telephone number, after showing her the "Wester Drumlins Collection."

Life in 1969
A few minutes after Sparrow's departure, however, Shipton is touched by the Weeping Angels and sent back in time to 1969 where he is found by the Doctor and Martha Jones and learns his destiny is to send a message to Sally Sparrow when he eventually lives his life back to 2007. An unfortunate aspect of the Doctor's instructions is that Billy receives the knowledge of when he will eventually die.
 * Exactly when Shipton arrives in 1969 is not indicated, but it is likely during the first half of the year as Martha says he has the Apollo 11 moon landing to look forward to.

Marriage and Easter Egg
In the ensuing decades, Shipton marries a woman named Sally, and eventually becomes involved in the video publishing industry, including, eventually DVDs. It is through his efforts that a videotaped message from the Doctor (which presumably he kept safe all these years) eventually ends up as an Easter Egg on 17 different DVD releases, sparking interest on the Internet and, ultimately, Sparrow's friend Larry Nightingale.

Death
Near the end of his life, Shipton found himself hospitalized, not far from where his younger self was working at the police station and meeting Sally for the first time. For Sally only a few minutes passed from her discovering that Billy had gone missing from the station's parking garage and receiving a phone call from the now-elderly Billy. She joined him in his hospital room, and it didn't take long for Billy to convince Sally that he was the same man she had just met and flirted with.

He revealed to Sally that he had married a woman named Sally after travelling to 1969, and had gotten into the video publishing business and was responsible for the Doctor's Easter egg message appearing on a number of DVDs. He finally delivered the Doctor's message: "Look at the list," and said the Doctor had told him he would never understand what the message meant. He had come to terms with this, and with his lost life in the 21st century, and with the fact that he knew when he would die, with the knowledge that he had a final meeting with Sally Sparrow to look forward to.

Knowing that he would die when the rain outside stopped (Sally notes it's the same rainfall that was occurring when she first met him), Sally stayed with Billy until he passed away. Soon after, she realized that the "list" in Billy's message was a list of her complete DVD collection, leading her forward into resolving the paradox. (DW: Blink)