Martha Jones' mobile phone

Martha Jones had a clamshell mobile phone that was later given to the Tenth Doctor to call him to Earth after Martha stopped travelling in time and space.

It was carried by the Archangel Network. (TV: The Sound of Drums)

Martha called her family about her brother Leo's birthday party that evening on her way to work, and later while working at Royal Hope Hospital. (TV: Smith and Jones)

The Doctor upgraded Martha's phone to a superphone with universal roaming shortly before they arrived on the SS Pentallian in the Torajii system. Martha called her mother Francine three times on the Pentallian. At this point her telephone number was 07711 911905. (TV: 42)

After blew up her flat in London, Martha called Francine and Tish as Saxon's people captured them, and warned Leo to stay with Boxer in Brighton. The Doctor used the phone to tell the Master that Gallifrey, the Time Lords, and the Daleks were more or less all gone. (TV: The Sound of Drums)

When Jack Harkness undid the Year That Never Was by destroying the paradox machine, Martha phoned Tom Milligan, whom the Master shot in the aborted year, to find he was alive. Deciding to stay behind to look after her family that retained memories of the devastating year, Martha gave the Doctor her phone. She insisted that he would "come running" to her when she called that phone, (TV: Last of the Time Lords) which he later did. (TV: The Sontaran Stratagem) At this point the number was 07700 900461. (TV: The Stolen Earth)