He even consulted his own horoscope in one of the papers, the one written by a disreputable friend of his who toiled unscrupulously under the name of The Great Zaganza. First he glanced at some of the entries under other birth signs, just to get a feel for the kind of mood the GZ was in. Mellow, it seemed, at first sight. “Your ability to take the long view will help you though some of the minor difficulties you experience when Mercury . . . ,” “Past weeks have strained your patience, but new possibilities will now start to emerge as the sun . . . ,” “Beware of allowing others to take advantage of your good nature. Resolve will be especially called for when . . .” Boring, humdrum stuff. He read his own horoscope. “Today you will meet a three-ton rhinoceros called Desmond.”

Dirk clapped the paper shut in irritation, and at that moment the door suddenly opened. The actor emerged with a purposeful air. He was carrying a small suitcase, a shoulder bag, and a coat. Something was happening. Dirk glanced at his watch. Three minutes past ten. He made a quick note in his book. His pulse quickened.

A taxi was coming down the street towards them. The actor hailed it. Damn! Something as simple as that. He was going to get away. The actor climbed into the cab and it drove off down the street, past Dirk. Dirk swivelled to watch it, and caught a momentary glimpse of the actor looking back through the rear window. Dirk watched helplessly and then glanced up and down the street in the vain hope that . . .

Almost miraculously a second taxi appeared suddenly at the top of the street, heading towards him. Dirk shot out an arm, and it drew to a halt beside him.

“Follow that cab!” exclaimed Dirk, clambering into the back.

“I been a cabbie over twenty years now,” said the cabbie as he slid back into the traffic. “Never had anybody actually say that to me.”

Dirk sat perched on the edge of his seat, watching the cab in front as it threaded its way through the slow, agonising throttle of the London traffic.

“Now that may seem like a little thing to you, but it’s interesting, innit?”

“What?” said Dirk.

“Anytime you see anything on the telly where someone jumps in a cab, it’s always ‘Follow that cab,’ innit?”

“Is it? I’ve never noticed,” said Dirk.

“Well, you wouldn’t,” said the cabbie. “You’re not a cabbie. What you notice depends on who you are. If you’re a cabbie, then what you especially notice when you watch the telly,” continued the cabbie, “is the cabbies. See what the cabbies are up to. See?”

“Er, yes,” said Dirk.

“But on the telly you never actually see the cabbies, see? You only see the people in the back of the cab. Like, the cabbie’s never of any interest.”