There was no mistaking the sound: it was that of a stealthy footfall, and it appeared to come from the staircase leading to the next floor.

Lord Bygrave left the Ministry on Friday evening, with plans for a fortnight's holiday in the country. But the following morning he had seemingly vanished into thin air. Now Scotland Yard are struggling to find evidence of foul play in the absence of tangible clues. A national newspaper is offering a reward for information about the Minister's disappearance - whether Bygrave be dead or alive.

Anthony "Algernon" Vereker, Lord...