This is a mythical country created by John and Yoko in 1973. It was announced on the Mind Games album, which included the Nutopian International Anthem, a track which contained only a few seconds of silence. John and Yoko wrote of Nutopia on the inner sleeve of the album (see text below). Their imaginary realm required its citizens to have no passports. It was a place without boundaries. And John and Yoko invited everyone to pledge their allegiance to Nutopia, whose flag was pure white and whose system of government was that of Cosmic Law. John and Yoko also requested that Nutopia be admitted to the United Nations.
This all stemmed from John’s ongoing immigration problems, the battle he had to constantly fight just to stay in America. On March 23, 1973, John was given a final order to leave the US within 60 days, while Yoko was allowed to remain indefinitely. The attempt to split the Lennon's up soon achieved its purpose, although not in the way the government expected (John and Yoko would separate for 18 months due to the intolerable level of stress in their relationship). The announcement of Nutopia came soon after this, on April 1 (April Fools Day), at a press conference in New York (there are photos that were taken on this day of John and Yoko waving the white flags--actually tissues--of Nutopia). This bizarre event signalled John’s retirement from active political life.
Here is the official declaration of Nutopia from the Mind Games liner notes:
DECLARATION OF NUTOPIA
YOKO ONO LENNON (with signature)
JOHN ONO LENNON (with signature)
One White Street
New York, New York 10012
April 1, 1973