End of Tom's fourth season now with The Invasion Of Time. A somewhat messy and confused story with some decidedly shoddy production designs, the story just about hangs together but has a number of problems. The Vardans are probably the worst realised aliens to ever feature in the series. Weird bits of tinfoil hanging in the air or some sorry looking soldiers hardly make for a threatening enemy (if you can, watch the story with the improved CGI effects on the DVD - it makes a huge difference.) The red herring of the story being over half way through and then the Sontarans suddenly materializing gives the story an added boost is very dramatic, but sadly things are then let down when Sontaran commander Stor opens his mouth and speaks with a cockney speech-impeded voice! And he looks cross-eyed! The protracted chase through the TARDIS comes across as silly and a blatant example of padding and the fact the the TARDIS interior looks like some disused hospital dispels any sense of this really being the TARDIS. The repetition of the TARDIS with the Doctor constantly tripping up gets tiresome too.
This is the first story where Tom's overracting too much and taking things less than seriously. We see him talking directly to camera, blowing a duck whistle, playing hopscotch in the citadel corridors and just looking like he's half cut some of the time (which he might have been!) He does, however, give an electrifying performance when assuming the mantel of presidency and shouting at the Castellan early in the story and for once you think the Doctor may really have gone bad.
Leela gets a dreadful goodbye - leaving to marry someone it appears she's said about two words to - totally unbelievable.
Invasion of Time is a bit of a rambling mess but has some enjoyable moments (many unintentional, like the Sonataran who almost trips up when chasing the Doctor), and Tom Baker being very silly - a trend that would continue over the next couple of seasons...