Episode One is missing, so the review will be based on Nicholas Courtney's introduction and Michael Palmer's reconstruction. Nicholas Courtney introduces himself and The Invasion, before filling the viewer in on the plot of episode one in a clear and consise manner.

The TARDIS reassembles itself as Episode One of The Invasion opens, before nearly getting destroyed by a missile fired from the dark side of the moon. Needing some TARDIS circuits repaired, the Doctor ends up at International E. During their meeting, the Doctor observed some inhuman behaviour in Tobias Vaughn... Michael Palmer has put together an impressive reconstruction of Episode One, that uses moving footage from other episodes, screen shots and images he's created himself. All of this conveys very effectively a real sense of what the orginal episode must have been like.

Episode Two opens with the Doctor and Jamie in trouble, Zoe and Isabel bonding, and Tobias Vaughn revealing his alien backers. The Doctor and Jamie have in fact be taken by friends - Brigadier Lethbridge-Stewart and his new command of a UNIT, a force to deal with extra-terrestrial threats and other paranormal events. It's good to Zoe's computer knowledge being put to use when she confuses the reception computer at IE, only to get hauled into Vaugh's office. The story is slowly building up - Vaughn is in league with aliens who have an interest in the Doctor, scientists are going into IE and emerging with changed personalities, and mysterious events are taking place at IE; it's all going at a pace which holds the viewer's attention, rather than boring them. It's also good to see the Brigadier again, the UNIT set up is introduced rather well and appears here to be a rather formidable force.

Vaughn and the Doctor meet once more as Episode Three begins; it's obvious that Vaughn has the upper hand, yet he allows the Doctor to meet with Professor Watkins. It's interesting to compare the attitudes of Vaugh and his head of security Packer - Vaugh is cool and controlled, where as Packer is very impulsive; even when he's angry, Vaugh still retains control of his emotions. On the run from Packer's men, the Doctor and Jamie find something moving in a packing crate...

Episode Four is missing, so the review will be based on Nicholas Courtney's comments and Michael Palmer's reconstruction. The video once more goes to Nicholas Courtney to fill in the gap, which does so once more in a smooth manner.

Episode Four opens with the Doctor and Jamie still evading capture, and looking for Isabel and Zoe. UNIT fly a helicopter in to rescue them, as Vaughn decides to move the invasion forward. This episode is a lot about moving things forward - getting UNIT and Vaughn completely at odds, getting the TARDIS crew back to UNIT head-quarters, moving the plot on to the big revelation as to Vaughn's allies. It works very well.

The Cybermen are revealed to be Vaughn's allies as Episode Five opens. Vaughn finally gets angry as it's revealed that UNIT will be able to act within 48 hours, but quickly regains control of himself. At this point Vaughn is in control of the Cybermen, and he is staging the Invasion via the sewer system of London. Professor Watkins machine's true purpose is revealed - Vaughn has a weapon that inflicts emotions on Cybermen, to devestating effectl Vaughn wants to rule the world himself and is using the Cybermen as his means of gaining the power he craves. Isabel comes up with a method for the Brigadier to capture proof of the Cybermen to convince his superiors, and then runs off to do it herself with Jamie and Zoe. Down in the sewers they encounter the damaged Cyberman... The location sequences so far have been nothing short of impressive, well chosen location and well directed sequences.

Episode Six opens with UNIT rescuing Isabel, Jamie and Zoe from the Cybermen - the battle sequence is quite impressive and well executed in such a small space. The Doctor is still puzzling over the the mysterious circuit included in IE products. In a quiet moment at UNIT, Captain Turner and Isabel bond. A sign of Doctor Who's low buget is when UNIT troops rescue Professor Watkins off-screen, which is a pity as the rest of The Invasion looks superb. The Doctor and professor Watkins uncover the true purpose of the mysterious circuit, and start fitting UNIT with a blocker just as the invasion begins... The sequence showing the Cybermen coming out of the sewers all over a deserted London forms a very impressive and memorable cliffhanger.

Vaughn seems pleased with the progress of the invasion as Episode Seven begins, but the Cybermen still see the invasion as their show. Fleeing back to UNIT HQ, Jamie is wounded. As UNIT prepares to take on the incoming Cyber-fleet, the Doctor sneaks into IE headquarters. The scenes where the Doctor confronts Vaughn is extremely powerful, with both Patrick Troughton and Kevin Stoney put a lot of energy into these scenes. Zoe once more gets to use her computer skills, successfully calculating a missile launch pattern that takes out a Cyberfleet that outnumbers the missiles, resulting in the Cybermen taking control of the invasion and changing the outcomes to the complete destruction of all life on Earth...

Episode Eight opens with celebrations at the Denfense Base ending as news of the Cybermen's plans reaches them. At IE, Vaughn destroys the Cyber-device in his office, but it is too late - the Cybermen on Earth now no longer follow his orders. As the Doctor and Vaughn race to switch off the radio transmitter, UNIT troops and Cybermen engage in battle. These sequences are well filmed, making excellent use of the location, as does the Doctor and Vaughn's run through the IE complex. With the Cybermen destroyed, and the TARDIS circuits repaired, the Doctor and his companions depart from Earth once more...

Derrick Sherwin's script allows The Invasion to build up at a suspensful pace, introducing each concept clearly and allowing various plot lines to flow without being rushed. Douglas Camfield's direction is superb throughout, with the location footage looking extremely impressive. Don Harper's incidental music became at a couple of points rather intrusive, but for the majority of the time it suited when used. This is really UNIT's story, and they get an excellent introduction, being shown to be a compotant force that overcome government red tape and not overly needing the Doctor's assistance. The Cybermen are surprisingly sparingly used for the first three-quarters of the story before emerging as a serious threat for the last two episodes, eclipsing Vaughn. An engrossing story.

8.2/10

Next time: The TARDIS crew's 'high brains' awaken an alien power...