That creature had gone a little way when she began to limp and show every sign of being foot-sore.

Presently she came to a halt, and hailed a four-wheeler which was passing.

I managed to be close to her so as to hear the address, but I need not have been so anxious, for she sang it out loud enough to be heard at the other side of the street, 'Drive to 13, Duncan Street, Houndsditch,' she cried.

This begins to look genuine, I thought, and having seen her safely inside, I perched myself behind.

That's an art which every detective should be an expert at.