It Auton be a Delgado tale

So from Troughton on to the action-man, largely earth-bound, anti-authority third incarnation of Jon Pertwee. And he's also superb. Don't allow anyone to suggest that earth-bound means 'dull'. Far from it.

Building on from the blueprint of The Invasion, this era has some top tales - with Day, Silurians, Mind all worthy of mention - as is the Green Death. 

The 'one with the maggots' is a very very close second for me. It's got the moral backbone, emotional farewell, memorable computer (Steeeeeeevens) and a cross-dressing Pertwee (!) at the top of his game.

Still, I'll jump from the end of the Jo Grant era to the start, and plump for Terror of the Autons.

Terror is positively teeming with iconic moments - the arrival of Roger Delgado's Master (it wouldn't feel right not picking one of his stories), the Auton policemen, the creepy chair death and the equally creepy toy killer.

Then there's the circus (can't see one these days without expecting the Master to pop out...!), some decent cliffhangers and the aforementioned beginning for Jo. 

I suppose it could be argued that the plot that strings these moments together is a tad on the flimsy side and the ending doesn't quite suffice. Still, they're more than outweighed by some wonderful material...and all from the pen from the superb Robert Holmes