Here's a short story:

CHAPTER VII. THE HOUSE IN SOHO 

WHITTINGTON and his companion were walking at a good pace. Tommy started in pursuit at once, and was in time to see them turn the corner of the street. His vigorous strides soon enabled him to gain upon them, and by the time he, in his turn, reached the corner the distance between them was sensibly lessened. The small Mayfair streets were comparatively deserted, and he judged it wise to content himself with keeping them in sight. 

The sport was a new one to him. Though familiar with the technicalities from a course of novel reading, he had never before attempted to "follow" anyone, and it appeared to him at once that, in actual practice, the proceeding was fraught with difficulties. Supposing, for instance, that they should suddenly hail a taxi? In books, you simply leapt into another, promised the driver a sovereign--or its modern equivalent--and there you were. In actual fact, Tommy foresaw that it was extremely likely there would be no second taxi. Therefore he would have to run. What happened in actual fact to a young man who ran incessantly and persistently through the London streets? In a main road he might hope to create the illusion that he was merely running for a bus. But in these obscure aristocratic byways he could not but feel that an officious policeman might stop him to explain matters. 

At this juncture in his thoughts a taxi with flag erect turned the corner of the street ahead. Tommy held his breath. Would they hail it?  (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: who held thier breath ?
Guess: Tommy

Question: what was a new one to them ?
Guess: sport

Question: who was walking at a norman speed ?
Guess: WHITTINGTON

Question: and who else ?
Guess: his companion

Question: what was deserted ?
Guess: Mayfair streets

Question: were they large ?
Guess: no

Question: what size ?
Guess: small

Question: what streets were someone persistently running ?
Guess: London

Now answer the following question in the same format.

Question: why did he have to run ?

there would be no second taxi