Another constable advanced inquiringly.

"I don't think so," he replied, in answer to Colin's question; "but if you like to wait a moment I can let you know for certain."

He disappeared within the building, returning after a short absence with a significant shake of his head.

"No one's heard anything of him yet, sir. They expect him at two o'clock, though."

"I know," said Colin. "I've got an appointment with him." He paused. "Can I leave the car here until then?"

The constable scratched his head. "Well, this ain't exactly a garage," he replied doubtfully. "Still, if you back her up quite into that corner——"

He turned aside as he spoke, and, pocketing the five shillings which Colin slipped into his hand, sauntered back to his former position.

* * * * * * * * *

With the best part of an hour and a half before him Colin came out into Whitehall and paused irresolutely on the edge of the pavement. Of all the tasks with which an impatient man can be confronted, that of killing time is perhaps the most trying. He was not in the least hungry, and, in any case, there was something ghastly in the thought of sitting all that while in a half-empty restaurant, brooding miserably over what might have happened to Nancy. If he wished to keep his nerves steady, it seemed to him that some form of exercise was imperatively needed, and, without hesitating further he made his way across Parliament Green, and struck off westward along the Embankment.

The soundness of his instinct was proved by the fact that when he arrived back at Westminster Bridge, after a vigorous tramp of about six miles, he felt that, whatever the next few hours might bring, his mind and judgment were once more under proper control. The hands of Big Ben were already at five and twenty minutes to two, and, knowing that there was a public telephone in the station, he crossed the road and entered the box. After a brief delay he succeeded in getting Mark's number.