The opening is laugh-out-loud funny: a propaganda broadcast in the style of bad sci-fi TV (complete with obviously botched bluescreen), glamourising the heroics of war. Meanwhile, the planet Atrios is being bombed back to the stone age by its twin Zeos, as its Marshal does his best Winston Churchill impression (John Woodvine even parodies the cadences of the PM’s wartime speeches as he claims, ‘Our ships… Dominate… their skies’) and the earnest, outspoken Princess Astra, who’s clearly had to visit one bombed-out hospital too many, pleads for peace and secretly negotiates with the enemy (and gets called ‘Your highness’ a lot – more Star Wars influences).

As a production, this looks fittingly grim, but has a sort of grandeur to it as director Michael Hayes incorporates touches like the sweeping camera that begins by revealing Lalla Ward’s Princess Astra before pulling back and round to take in the whole war room. The lighting is kept low: this bunker looks gloomier and more claustrophobic than the Kaleds’. All this, plus the Doctor’s warning about the Black Guardian give a palpable sense of impending doom.

It’s not all gloomy, though. I wonder how much input Douglas Adams had to the script beyond the final scenes of Part Six. The TARDIS scenes in this are pretty great: the Doctor and Romana bantering away (‘Where’s your optimism?’, ‘It opted out.’; ‘What a lot of zeroes’), and maintaining a generally glib demeanour as they’re captured, interrogated and threatened with death – although the Doctor comes close to losing his sense of humour with the Marshal. By this stage, Baker and Tamm are a fairly compelling double act, and it’s fun to spend time in their company. Their little yes/no interrogation routine is cute. For a serial that’s got one of those reputations, this is pretty good so far.

Next episode: The Armageddon Factor – Part Two