"What are you concealing from me, boy?"

Not enough, some might say, for this is Castrovalva - where Master Waterhouse introduces the innocent and unsuspecting viewer to "Little Matthew"

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But that's not the only harrowing element of the Fifth Doctor's first outing. The Time Lord himself is made incompetent (and incontinent?) by his regeneration but still gets to go on a self-propelling wheelchair and pulls off decent impressions of his former selves - and Basil Fawlty (the War Hotelier).

Tegan gets hot and bothered, Nyssa gets moist and, of course, Adric has a semi on, before they all meet Chardonnay Shardovan and his sheep-in-wolf's-clothing chums.

There's a fly in the ointment, of course, and this one has a risible, raisable platform, a double-decker perspex top hat and a penchant for looking at boys on the dark web.

But does the new Doctor bowl Jim and Martin over? Or is he out first ball?

Find out here.