By 1968 Patrick Troughton had been playing the lead role in the BBC TV series Doctor Who for two years and the Invasion would take the show into different directions. The Invasion also saw the return of well-known adversaries in the guise of the Cybermen.
The Doctor had already had to stop the Cybermen before yet in the Invasion they would make their most determined attempt to take over the Earth. The idea for the plot of the Invasion originally came from Kit Pedler and the story was reworded by the script editor Derrick Sherwin. The Invasion was rewritten in order to
prepare Doctor Who for the 1970s and a new Doctor as Patrick Troughton was only going to do one more season. He was joined by his usual co -stars Frazer Hines and Wendy Padbury. The cast of guest stars included some highly regarded actors. This eight episode story was produced by David Bryant and directed by Douglas Camfield. Also featurred was Camfield's wife Sheila Dunn who did the voice of the computer.The Doctor, Jamie, and Zoe start the story in contemporary London and find themselves in the midst of a well hidden plot by the Cybermen to take control of the world's major cities. They inadvertently stumble upon the Cybermen
conspiracy when they investigate the vanishing of one of the Earth's most accomplished scientific researchers. The Doctor finds himself a new ally in the form of the United Nations Intelligence Taskforce (UNIT) an organisation that would be prominent during the Third Doctor's tenure in the TARDIS.Together the Doctor and UNIT have to stop the ruthless Tobias Vaughan as well as the Cybermen. The ambitious Vaughan allied himself with the Cybermen in the belief that he could dominate the world without them controlling him. The Doctor worked well with the UNIT commander Brigadier Lethbridge – Stewart as played by Nicholas Courtney. So good was Courtney's performance he was subsequently featured in many stories until the arrival of the Fourth Doctor. The Invasion was a ground breaking saga and its positive impact was increased by an excellent supporting cast featuring Kevin Stoney, Sally Faulkner, and Peter Halliday. The directing of Camfield is top notch, especially the battle scenes. Episodes two and four were lost. However prior to the release of the DVD these episodes were animated and combined with tape recordings. Courtney had recapped events in the lost episodes for the video release in the 1990s.
