Alison Docherty (The Year That Never Was)

Professor Alison Docherty spent a Year That Never Was living on an Earth ruled by and his army of Toclafane. With the promise of information on her son whom she presumed dead, Docherty became an informant for the Master. She worked out of a repair shed at Nuclear Plant Seven.

Biography
During the "Year That Never Was", she feared she had lost her son in the attack. Tom Milligan took Martha Jones to her lab, where Docherty helped them capture a Toclafane.

She asked how Martha was going to defeat. Martha said that she had a gun loaded with chemicals that could kill the Master despite his ability to regenerate. Docherty doubted this: "You might be many things, but you don't look like a killer to me".

When Martha and Tom left for the slave quarters at Bexley, she used a secret video link to the Valiant, the Master's base. She told the Master the whole plan in exchange for information about her son. This however was planned for by Martha; the resistance knew that she was a possible information leak. (TV: Last of the Time Lords)