Alison Docherty
Alison Docherty was a woman in her late fifties and was a survivor of the 2008 Toclafane attack.
During 'Year That Never Was', she feared that she had lost her son due to the attack. Tom Milligan took Martha Jones to her lab where she found out how Martha was going to defeat the Master. Martha said that she had a gun loaded with chemicals that could kill the Master despite his ability to regenerate.
When Martha and Tom left into London she had a secret video link to the Valiant, the Master's home base at that time. She told the Master the whole truth on the plan. This however seemed to be planned by Martha all along.
When that version of 2009 was erased and time was bound back. Subsequently, though Alison did not know why, Martha gave her a gift of flowers as a way of saying thanks and that she didn't blame her. She was wearing the scarf of Newnham College, Cambridge. (DW: Last of the Time Lords)