Each house had three floors; each front door opened on to the street and led to a narrow passage and a narrow flight of stairs. Most of the small front windows were covered with lace curtains, many frayed, some of them dirty; but here and there the curtains were fresh and bright and in the window of Number 49 was a bowl of blazing scarlet tulips.

“What have you done to your hand?” asked Snub.

“I was bitten by a dog.”

“Mad dog?”

“At the moment probably insane but with any luck he’s cooling off in a police cell.”

“You are a one,” said Snub—and when Rollison paused outside the door of Number 51, without a smile enlivening the grimness of his expression, Snub frowned. “Sorry. Expect violence?”

“I’ve told you I don’t know what to expect. Try the front door, will you?”

“I could hop round the back,” suggested Snub.

“Later, maybe.”

Snub tried the front door and found it locked. At the window of the front room a curtain, more grey than white, moved as if stirred by the wind but the window was tightly closed.

“Watching eyes,” muttered Snub. “Ought we to be together?”

Rollison lifted the brass knocker which hadn’t been cleaned for days and was dull and green, spotted with verdigris. The sound of his knocking echoed up and down the street. Two men, one young, one very old, cycled past, staring at both the men and the car.

Shuffling footsteps sounded inside the hall.

“Get back a bit,” said Rollison.

Snub stood three yards away from him, wary and watchful. The lock clicked and the door opened a few inches. Rollison saw a slatternly old woman with thin grey hair in curlers. She clutched the neck of her drab black dress.