All we can infer (from the archaeological shards dug up in Berkshire, Devon and Yorkshire) is that the first Britons, whoever they were and however they came, arrived from elsewhere. The land (Britain) was once utterly uninhibited. Then people came.
All around the world, tourist boards advertise trips to Britain with images of the great castles and cathedrals that occupy the commanding heights of our landscape. They seem timeless and typically English. It is rarely mentioned that they are predominately French - proud monuments to the invasion that signals the end of England's 'dark age'.
Other unsolved murders or untimely deaths were readily blamed on the supposedly sinister Jews: If a Jewish doctor failed to save a life, the whole Jewish community might be attacked and fined.