Renowned Iranian sculptor Parviz Tanavoli has been barred from leaving the country the day before he was due to speak at the British Museum.

The veteran artist’s sculptures are included in the Tate Modern’s rehang alongside paintings by Warhol and Lichtenstein in a room called Beyond Pop. They were also featured in Tate Modern’s exhibition The World Goes Pop last year.

Iranian authorities confiscated the artist’s passport early on Saturday morning while he tried to board a flight out of Tehran’s Imam Khomeini International Airport. Tanavoli was told by border officials on 2 July at Tehran’s Imam Khomeini International Airport that he could not leave for London. The artist, who divides his time between Tehran and Vancouver, still doesn’t know why he is kept there.