Brian Randell later wrote that : Colossus documentation and hardware were classified from the moment of their creation and remained so after the War , when Winston Churchill specifically ordered the destruction of most of the Colossus machines into `` pieces no bigger than a man 's hand '' ; Tommy Flowers was ordered to destroy all documentation and burnt them in a furnace at Dollis Hill .
They stayed so after the War , when Winston Churchill ordered the destruction of most of the Colossus machines into `` parts no bigger than a man 's hand '' ; Tommy Flowers himself burned the designs in a fireplace at Dollis Hill .