Projekt-26, best known as P-26, was a stay-behind army in Switzerland charged with countering a possible invasion of the country. The existence of P-26 (along with P-27) as secret intelligence agencies dissimulated in the military intelligence agency (UNA) was revealed in November 1990 by the PUK EMD Parliamentary Commission headed by senator Carlo Schmid. The commission, whose initial aim was to investigate the alleged presence of secret files on citizens constituted in the Swiss Ministry of Defence, was created in March 1990 in the wake of the Fichenaffäre or Secret Files Scandal, during which it had been discovered that the federal police, BUPO, had maintained files on 900,000 persons (out of a population of 7 million).
Since the existence of P-26 was revealed a month after similar revelations made in Italy by the premier Giulio Andreotti, who disclosed to the Italian Parliament the existence, throughout the Cold War, of a Gladio stay-behind anti-communist paramilitary network headed by NATO and present in most European countries, Switzerland formed a parliamentary commission charged of investigating alleged links between P-26 and similar stay-behind organizations. It was one of the three countries, along with Belgium and Italy, to create a parliamentary commission on these stay-behind armies.
Swiss authorities declared on November 21, 1990 the dissolving of P-26, since the clandestine organization operated outside of parliamentary and even governmental control, being an autonomous structure hidden inside the secret military services.