4 January 2011I've only checked the British Museum website today, but the the previous press announcements (first link above and background link below) imply that it was not posted until well after 4 January.
Extension of Cyrus Cylinder loan
Following a request from the Iranian Cultural Heritage, Handicraft and Tourism Organization (ICHHTO), the Trustees of the British Museum have agreed to extend the loan of the Cyrus Cylinder to the National Museum of Iran until 15 April 2011. This decision has been taken in recognition of the fact that the exhibition has proved to be very popular to date, and the extension will give an opportunity for people from the provinces including school groups to visit the exhibition during the Norouz (New Year) holidays around 20 March 2011.
The Trustees are delighted that the loan has been such a success and look forward to continuing the Museum’s collaboration with colleagues in Iran in the future.
Background here.