This is the best Doctor Who so far, an impeccable eight episodes. It is very from what has come before.

Its exciting to see The Doctor return a setting which was used so successfully in The Web of Fear. We are treated to a return of Lethbridge-Stewart (now promoted to Brigadier). The invention of UNIT is absolutely genius, rather than using generic army characters we can get to know a specific group of soldier specialists who are accustomed to The Doctor and have a great rapport with him and his fellow travelers. The frequent mentions of Professor Edward Travers (from The Abominable Snowmen and The Web of Fear) rewards long term viewers who are highly invested in the show.

The story is driven by a suspicion of electronics, which The Doctor apparently hates. Note the word "suspicion", which pretty much sums up the tone of this action spy thriller. This feeling of distrust is focused on International Electromatics, the world's largest and most advanced electronics manufacturer.

The Doctor, Jamie and Zoe's search for Travers leads them to the outstanding character Isobel Watkins. I desperately wish this wasn't her only story. Watkins' uncle has gone missing which instigates an investigation.

Zoe and Isobel have a wonderful story together. Their chemistry on screen is that of best friends, they look like they are really enjoying acting against each other. I love how intelligent Zoe is throughout, especially when destroying the hilarious answer-phone computer and the not so hilarious Cybermen ships with logic.

I felt an effort was being made throughout The Invasion to show that women can be clever, ambitious and witty whilst still being women. This kind of proto-feminism would come across a little patronising today, but in the context on 1960s children's television I felt it mostly worked. There were other elements of the gender politics in this story which didn't work so well - but hey, at least they were trying to tackle the issue!

Tobias Vaughn is proof that you can make a character totally unreasonable and insane yet give them a believable characterisation and clear motives. From the very start the audience know that Vaughn will be betrayed by the Cybermen, but we are given plenty enough explanation as to why he wanted to help them. This makes the inevitable ending to this relationship far more satisfying to watch - his logic was proven to be wrong. "Is this what you wanted? To be the ruler of a dead world?" I love the Doctor...

The Cybermen are a wonderfully visual enemy. Because we have seen them before and understand their motives we are able to focus on other elements of the story leaving the Cybermen to do what they do best by looking ominous and creepy.

With the benefit of hindsight I can see why the show will end up heading in the direction it does during the third Doctor's era. The Web of Fear and The Invasion are so credible, enjoyable and well realised. The writers of Doctor Who have found a way to make the show thrive in this modern day action environment. This is not to say that this is the only setting in which Doctor Who thrives (far from it) but I can see why they would want to capitalise on these kinds of stories when the more sci-fi stories of this series were failing to reach the same levels of quality.