In all memory there is a degree of fallenness; we are all exiles from our own pasts, just as, on looking up from a book, we discover anew our banishment from the bright worlds of imagination and fantasy. A cross-channel ferry, with its overfilled ashtrays and vomiting children, is as good a place as any to reflect on the angel who stands with a flaming sword in front of the gateway to all our yesterdays.