‘It’s the Christmas holidays and a Doctor Who spin-off is on BBC One! It’s got Sarah Jane Smith and K9! Sure, there’s an annoying youngster and the story’s a bit of a knock-off of a past Who adventure, but it can’t possibly fail!’

Well, 1981’s K9 and Company did fail, becoming the Whovian equivalent of the Star Wars Holiday Special. Revisiting the idea was brave to say the least and it’s probably only Russell T Davies who could have pulled it off.

The 2006 nu-Who episode ‘School Reunion’ cannily bought Elisabeth Sladen back as Sarah Jane for a seemingly one-off return to carefully marry the series’ past and present in an audience-friendly way. The character’s return was successful enough for Davies to launch his own K9 and Company and New Year’s Day 2007’s ‘Invasion of the Bane’ was the result. With a sense of fun for all ages, the one-hour pilot sensibly riffed a decent Who story (‘Spearhead from Space’) instead of an average one (‘The Stones of Blood’).

Moreover, it moved Sarah Jane Smith through time from Plucky Girl Reporter to Cool Auntie, with a sonic lipstick and a supercomputer in the attic, while losing nothing of what people liked about her in the first place. A CBBC series duly arrived the following autumn: SJA was bright and breezy, yet emotional and reflective in nicely judged measures.

Sarah Jane was joined by Maria (Yasmin Paige), the ultra-sensible ‘eyes’ of the audience; Luke (Tommy Knight), an alien-human and Sarah Jane’s adopted son, who despite his intelligence, struggled with the ways of the world; and the streetwise Clyde (Daniel Anthony), who went from comedy wise-guy to de facto hero later on.

When Paige left the show, Rani (Anji Mohindra) took her place as the feisty younger female heroine and mercifully wasn’t half as wet. Throw in their various parents – more often than not presented as cartoon characters (hello, Maria and Rani’s mothers) – and you have a solid ensemble. Poor K9 was kicked into touch; sent off to deal with a black hole most of the first few series, no sooner did he return than he was posted off to Oxford with Luke.

Fan-friendly crossovers with the parent show included the Slitheen (who worked much better in a CBBC environment), Judoon and Sontarans all calling in. Then who should reappear? Brigadier Lethbridge Stewart, in a lovely swansong from Nicholas Courtney, followed by not just one Doctor, but another one! With Jo Grant thrown in!

The beauty of episodes like ‘The Wedding of Sarah Jane Smith’ and ‘Death of the Doctor’ is that parents watching with children remember the old days, whilst the children are smart enough to recognise this without it getting in the way of a good story. Wisely, the guest stars don’t get in the way too much, with Tennant and Smith in particular not gate-crashing to the regulars’ detriment. Speaking of guest stars, the calibre was remarkably high, with Samantha Bond, Niger Havers and Bradley Walsh all cropping up.

In many ways though, SJA fared best with its own original adversaries. The Trickster was a recurring foe who, with his (its?) eerie blank face could be guaranteed to induce nightmares; the red and yellow robots from ‘The Empty Planet’ (2010) were superbly realised; whist the body-hopping lizard Androvax from ‘Prisoner of the Judoon’ (2009) and ‘The Vault of Secrets’ (2010) was another memorable enemy.

Standing above all, however, was Elisabeth Sladen. An actress that knew her character inside out and matured alongside it, she reinvented Sarah Jane as the closest we’ll get (for now) to a female Doctor. Sarah Jane’s bravery was shaped by the one true constant in her life, though she felt his absence all too painfully, gaining solace in the day job and her young friends.

Sladen consistently looked some 15 years younger than she was and took on a frequently physical role with zest. Her passing earlier this year came as a shock which even watching the final episodes will be hard to shake off.

Many fans will say Lis didn’t have the career she deserved, but maybe that’s not the point. Some actors only need one character to define them (think Bill Owen or Gorden Kaye) and Elisabeth Sladen had Sarah Jane Smith. That’s all she needed, and we were all better off because of it.

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