When I looked at my watch, and realised that it was impossible to get down, I left the bag as it was, half-packed and went outside to the tube station and telephoned." "How did you get in and out ?" asked Tarling.

"The porter on duty at the door said he saw nobody." "I went out the back way," explained Mr.Milburgh.

"It is really the simplest thing in the world to get into Miss Rider's basement flat by way of the mews behind.

All the tenants have keys to the back door so that they can bring their cycles in and out, or get in their coals." "I know that," said Tarling.

"Go on." "I am a little in advance of the actual story," said Milburgh.