She decided to go to the left. As she approached the end of the road, she slowed down; the car behind her did not, and Mma Ramotswe had to move swiftly off to avoid being bumped into. She hardly dared look in her mirror as, hunched over the steering wheel, the ancient engine of the tiny white van straining every metal sinew, she careered down the road in the direction of the hospital. At the roundabout, she threw the vehicle with vigour into the circling traffic, narrowly missing a truck, which sounded its horn angrily. “I’m very sorry, Rra,” she muttered under her breath. “I am being chased. That is the only reason why I’m driving like this.”

She had now passed the Anglican cathedral and was alongside the piece of ground used as a school playing field; hardly a field, just a large square of level red earth, kicked into dust here and there by the feet of the children. Mma Ramotswe noticed that there were small boys running about; two teams in identical khaki trousers and blue shirts, mostly barefoot, were pursuing a dusty football. A match was in progress. She saw the parents, lined up along the edge, shouting support for their sons.

She saw her chance, and turned the tiny white van sharply off the road, pointing it at a parking place between two parental vehicles on the verge. She would be perfectly safe here, amongst all these people, some of whom she was bound to know. Clovis Andersen, she thought, would approve.

The car behind her stopped halfway off the road. Mma Ramotswe watched in her mirror as it drew level with her. She held her breath; she had not expected such effrontery, not from somebody described in The Principles of Private Detection as a tail. Tails, surely, would be more discreet, fading off into the background when one stopped and looked at them.

The car had slightly tinted windows, which made it difficult to see the face of the person at the wheel. But now, directly behind the tiny white van, preventing it from returning to the road had Mma Ramotswe wished to do so, the car revealed its driver.

“Mma Ramotswe,” shouted a voice. “I was trying to catch you! I’ve got something for you.”

She glanced in the mirror and then turned round in shock. Through the driver’s window, now fully wound down, she could make out the familiar figure of Mma Potokwane, matron of the orphan farm, gesticulating frantically.

Mma Ramotswe took a deep breath. She knew that in a moment or two she would see the humour in the situation, but not just yet. A good minute had passed by the time she opened the door of the van and made her way towards Mma Potokwane’s car.

“My goodness, Mma,” shouted Mma Potokwane. “You were driving like one of those young men from the garage. What was the hurry?”