Elisabeth Sladen – who played probably the best-loved Doctor Who companion ever, Sarah Jane Smith – died on Tuesday. Like so many fans, I'm bereft.
Why was Sarah Jane so important? Doctor Who always had strong female characters, but unlike, for example, Zoe, the astrophysicist who lived on a space station, Smith was an attainable role model. An investigative journalist in modern-day Earth, her first appearance in the 1970s found her relentlessly pursuing a story – and refusing to make the Doctor a coffee. She was strong, funny and determined. And unlike some female companions before her, she didn't constantly trip, twist her ankle and scream "Doctor!"
The genius of Doctor Who is that the Tardis can travel anywhere in time and space – it can never run out of stories. The weakness is that there's always an escape route – why stay in the apocalyptic wasteland when you could be whisked away to a planet with a beach and cocktails? The answer is mostly character-led: the Doctor and his companions are driven by curiosity – and courage.
Elisabeth Sladen excelled in communicating that heart. Her Sarah Jane never lost her slight nerviness, the trembling lip that said maybe she'd prefer the beach-and-cocktails. She wasn't an action hero; she had to make the decision to be brave.
When Tom Baker's Doctor left her on a suburban street and she strolled off whistling merrily, the audience longed to know what happened next. When she returned in 2006 to Doctor Who, and her own show The Sarah Jane Adventures, we rejoiced – and hoped for many more years.
As I write this, I've just sent back the proofs of my first Doctor Who novel to the BBC. Selfishly, I'm mourning the fact that I'll never be able to write for Elisabeth Sladen. Along with many fans, I'll be donating to a cancer charity today, in her memory.