Andreas Wiseman International EditorEXCLUSIVE: BBC One has commissioned 9/11: The Twenty Year Anniversary, a feature length documentary marking the 20th anniversary of 9/11, from UK firm Top Hat Productions (Exposed: The Church’s Darkest Secret) and BAFTA-winning director Arthur Cary (The Last Survivors).The 90-minute film, which will air next year, will tell the story of the two-hour period when terrorist attacks on the Twin Towers, the Pentagon and Flight 93 changed the world forever.