Calvine UAP — UK Parliamentary Questions and MoD Release

The Calvine UAP incident of August 4, 1990 — in which two hikers photographed a large diamond-shaped craft over Perthshire, Scotland — generated a classified MoD investigation that spanned more than three decades. The Defence Intelligence Staff (DI55) conducted a technical photographic analysis and produced a classified assessment concluding the craft was between 25 and 100 metres in diameter and of 'unknown origin.' The assessment explicitly stated it was not a known British, American, or allied aircraft or experimental program. The photographs were classified SECRET and locked in DI55 files. Under the 30-year rule they should have been released in 2020; they were not. In 2021, journalist and UAP researcher David Clarke learned that a former MoD official had retained a copy and obtained permission to publish it. Clarke published the photograph in 2021. His publication prompted a formal National Archives release of the MoD's official Calvine files in 2022, ending a 32-year classification. Parliamentary questions from MPs about the photographs received formal government responses acknowledging the MoD investigation. The released DI55 assessment documents remain available at The National Archives (TNA) in Kew, London, where they are accessible to researchers. The Calvine case is considered the clearest government-analyzed UAP photograph released by any NATO nation.