A couple of hours later, she returned from Sheffield tired and frustrated. Pain was shooting up her leg, and she could feel her ankle had swollen to twice its size where she had twisted it at the cattle market. She had walked the streets of the city centre, hunting out the dark corners and following the sounds of the uneasy silences that lay beyond the bright lights around the pubs and night clubs. She had explored all the subways, lit and unlit, walking in areas most women would have avoided after six o’clock in the evening. She had visited a shelter for the homeless she had located north of the university.

But Sheffield was a big place. She might even have to widen her search to Rotherham and Doncaster. Fry knew it could go on for months or years, without success. But once she’d started, she would never be able to give it up.

When she reached Grosvenor Avenue, she noticed that the same figure was opposite the house again. He seemed to be watching a lighted window on the first floor. A peeping tom, no doubt about it. It was time to give him a nasty surprise.

Fry unlocked the front door and went into the hallway. She waited a minute, then switched off the hall light and took the bulb out of the fitting, in case one of the students came downstairs. Then she walked straight through the house and stepped out of the back door. She clambered over the garden fence and moved silently down the alley between the houses until she could emerge on to the road again.

She could see the man’s back now. His shoulders were hunched in a black or dark blue jacket, his hands in his pockets. He was totally unsuspecting. A pushover.

When she touched him, he jumped like a startled rabbit and tried to turn round.

‘What the –!’

But she already had him in a wrist hold, with her other hand above his elbow and his arm held straight out. From this position, she could force him easily to his knees, cuff him, do what she liked with him. The thought gave her a surge of satisfaction.

‘What’s your business?’ she said.

He kept very still. Now she was close to him, Fry could see he wasn’t a big man, though he was well wrapped up and wore a peaked cap. He said nothing, but kept his mouth tight shut and rolled his eyes towards her. She applied a bit more pressure to her grip.

‘Whatever it is, I suggest you go and do it somewhere else, mate.’