‘I met your people a long time ago. And some time off yet.’ What a great idea: pitting Sarah Jane against her first enemy and connecting it to the year’s big Doctor Who UNIT epic, ticking boxes for both old and new series fans. The call backs to The Time Warrior (including the crashed Sontaran sphere that needs to be repaired, and Sarah Jane revealing Kaagh like the third Doctor using his rhondium sensor) are very pleasing. But equally, this makes good use of repurposed footage from The Sontaran Stratagem.

At the time I was mildly irritated that Kaagh wasn’t played by Dan Starkey, purely because it works against the idea of the clone species. However, Anthony O’Donnell is good, and Kaagh is a stronger character than Skorr – ingenious, resourceful and slightly more impressive than most of his Tenth Fleet comrades. The cliffhanger, as Kaagh menaces Clyde with the promise of a Sontaran Experiment style fate, is very strong. Only the dodgy CGI helmet feels like an unnecessary embellishment.

Beyond that, this re-establishes the regulars well, with Clyde and Luke now firmly partners in crime. This helps to take the edge of Maria’s imminent departure: Sarah Jane’s frosty reaction to the news is informative. It reminds us that she’s become brittle and it doesn’t take much, even from friends, to make the walls come up. And there’s a hint of the Doctor’s own brusque dismissal of Sarah Jane in The Hand of Fear; a cold acceptance that this is the way things must be. Between the winds of change blowing through Bannerman Road and the most dangerous adversary the team has yet faced, this is really good.

Next Time: The Last Sontaran – Part Two