One of the good things about The Green Death is the way it instantly rehabilitates the Brigadier. In his last couple of scripts, the Brig has been a fairly reduced, comic relief character, with little of the steel and smartness that Nick Courtney brought to his appearances between Seasons Five and Eight. In The Time Monster and (to a slightly lesser extent) The Three Doctors he’s written as a comedy buffoon, apparently unable accept exactly the kind of strangeness UNIT was set up to handle. By The Three Doctors, even the loyal Benton suggests that his CO is having a nervous breakdown. So it’s a relief to get a scene like the Brigadier’s face-off with Stevens, declaring this is a security matter, and will be investigated by the UN, and it takes no-one less than the Prime Minister to make him back off. Later, at the lovely domestic dinner scene at the Nuthutch (the Brigadier, delightfully, has turned up in full evening dress), his incredulity at Professor Jones’ plan to go searching for a fabled mushroom in the Amazon is played as healthy scepticism rather than utter closed-mindedness. I’m so pleased Nicholas Courtney is again getting worthy material, even if he’s suddenly looking very much the middle aged Brig of the Fourth Doctor stories.

Indeed, after the ridiculous bunch in The Time Monster, Sloman seems to have discovered an ability to actually write believable characters (or maybe Terrance Dicks has just decided he’s going to script edit Barry Letts after all). This episode is full of intimate and relatable scenes: a boozy dinner at the Nuthutch; Stevens’ gossipy tête-à-tête with his subordinate Hinks, and best of all, Jo’s emerging relationship with Professor Jones. The way he comforts her over the death of Bert, with a little eulogy that’s genuinely touching, leads to an almost-kiss interrupted by the Doctor. Nonplussed by Jo’s obvious indifference to his trip to Metebelis 3, the Doctor cockblocks the Professor, leaving Jo to the mercy of a hatching maggot (very Freudian).

Earlier, the Doctor’s reunion with Jo in the mine almost feels like they’ve been brought back together after she’s already left him, like Martha in The Sontaran Stratagem, with the Doctor almost feeling like her companion for the episode in a way the series has never really done before. We’re starting to understand Jo can have a life without the Doctor in it – something that’s hard to picture for anyone, really, since Ian and Barbara (and they were always too dependent on the Doctor and the TARDIS to get them back home to ever seem true free agents).

So far, everything about The Green Death just works. Even BOSS, WOTAN with a personality, isn’t just a dull super computer like in Star Trek. Instead, it has quite a nice line in sardonic humour (‘You are a sentimentalist,’ it says to Stevens having ordered him to program the nominative-determinist Fell to hurl himself to his death. John Burrowes’ design works: the sterile, clean lines and opulent marble of Stevens’ office contrasting with the wood and soft furnishings at the Nuthutch. This is great.

Next episode: The Green Death – Episode Four