Cyber-invasion (Silver Nemesis)

In the year 1988, the Cybermen attempted to invade Earth. (TV: Silver Nemesis)

Behind the scenes

 * The Discontinuity Guide implies that the "CyberIsomorphs" were in fact native to the 20th century, descended from the Cybermen whom left Mondas. It was after they learnt of Mondas' destruction that they attempted to turn Earth into a new base planet.
 * Doctor Who: Cybermen claims that the Cybermen seen in Silver Nemesis were in fact late CyberNomads who used time travel to invade Earth in 1988, separate from the Neomorphs.