“K9’s in it this week!”

When did you know?

In 2005, when "Doctor Who" came back, it could have been a disaster. Or an underwhelming disappointment like 1986. Or an unmemorable piece of TV like the Randall and Hopkirk reboot.

When did you know? Not just that it was good, great, but that it was going to be more successful than ever?

I used to work as a facilitator at a youth theatre in Surrey with a fantastic bunch of 8-12 year olds. I remember in 2005, telling them they should all watch this new series called "Doctor Who" starting this Saturday. Many did.

One girl in particular, who we'll call Annie, loved it. Every week, she'd excitedly talk to me about the previous Saturday's best bits. She'd be around 15 now but was 8 or 9 then. I loved that someone of that age was so into my show.

So it was working, it was good and it was popular. Then one day in April 2006, a revelation. At the start of the session, I hear Annie talking to a boy we'll call Lee about last Saturday's werewolf. Then she excitedly says the immortal words:

"And K9's in it this week!"

How do you know what K9 is? Why does his presence excite you? How are you already so mired in Who lore that the tin dog is a bigger draw than the Krillitanes?

Reminds me of season 20, when Nick Courtney was so much more exciting than mutants or giant dogs. Suddenly this wasn't just a tv show for Annie.

Suddenly it was "Doctor Who." And that's when I knew.