Learned about this about an hour ago. Not something I, or any of us, was expecting to happen anytime soon. She seemed to have quite a way to go yet.
I'll admit that I haven't given Sarah Jane the kindest treatment in my commentaries, my being a New Whovian who had her expectations driven astronomically high, but I won't deny that she was a very solid companion and I can't put enough emphasis on the impact she's had on both the fandom and the Whoniverse. Even though I'm not in the generation of Whovians who grew up with her and Tom Baker in the '70s, I did get to see her come back as a reminder of both the poignancy of the Doctor's character and the longevity of the show as a whole. In a way, and this didn't really occur to me until a few days after Nicholas Courtney's death, the characters left behind by the actors of this great program will always have a certain immortality both on the screen and in the hearts of the fans.
In her honor, I'll be watching The Time Warrior after I finish The Web of Fear. I was intending to do a Nicholas Courtney serial after his passing and never made it until now, so now I'll have both of these fine actors' debuts back-to-back.
Elisabeth Sladen
1 February 1948 - 19 April 2011