As we make our way into the second half of season seven, UNIT and The Doctor investigate vanishing astronauts who have lost contact with Earth from Mars Probe 7.

Liz Shaw is fantastic in this story. She laps up this much more active role and looks really comfortable on screen. It struck me that her moody approach suits this more conspiratorial vibe - everything about her performance clicks into place in this one. Perhaps the problem with the Silurian seven-parter is that an apathetic response to ancient monsters beneath the Earth's crust is ludicrous to the point that it alienates the audience, whereas here it works.

I'm still adjusting to the new and improved pace of the show. Make no mistake, the general quality of Doctor Who has risen significantly and my expectations have risen with it. With the exception of Part Four of our last adventure, each episode of the 1970s so far are comparably exceptional when compared to its 1960s counterpart (my love for which, I have written about at length!!)

Was I wrong for being dubious over whether the decision to strand The Doctor on Earth was a good idea. Maybe this back to basics approach was what it needed, it is a program reevaluating itself.

Even though the idea behind this story is not as strong as Doctor Who and The Silurians I prefer The Ambassadors of Death. In this new, more "realistic" Doctor Who, old school looking monsters like the Silurians just don't look the part any more, they look unsophisticated. The Ambassadors however could not be more suitable - unnerving, slow moving, radiation reliant monsters in spacesuits. Monsters that can kill you just by touching you, who are silent and deadly. The concept and design is not just full of great ideas, but is achievable and translates well to the screen.

For the second story in a row we have to question who the real bad guys are. Just as the audience is confronted with good Silurians, it is revealed in this story that the aliens are being manipulated and used as weapons by terrible humans against their will. For the third story in a row we have corrupt officials abusing their position of power, surely a theme for this season.

The Doctor volunteering to pilot a rocket into the orbit of Mars is brilliant, ridiculous and about the most Third Doctor-ish thing I have ever heard of. Pertwee continues to be my favourite Doctor so far, he has many of the same serious / silly nuances that Troughton established but is an even more theatrical and entertaining hero.

Carrington is shown to have carried out his plan after being mentally disturbed after meeting the aliens on Mars Probe 6. Mental disturbance is becoming yet another theme of this season. In keeping with this it has been quite a dark series, so I am pleased that The Doctor finds the Spacemen unharmed, rather than dying they are mentally conditioned, in a more inventive and interesting punishment than death.

The alien being that reveals itself could have looked better but the fact that it is only demanding their alien ambassadors be returned makes the human villains so deliciously despicable. Especially considering that they had been sent to Earth to begin peaceful communication with humankind. The Doctor once again proves his upstanding morals by guaranteeing to return the ambassadors safely. The alien commander then becomes overzealous threatening to destroy the world if the ambassadors are harmed.