Three Thursdays in South London

Updated 5 October 2026 by Investigation Bureau

An illustrative case story. It is a composite built from the kind of work our investigators have handled over the years. Names, places, dates and identifying details have been changed or merged so that nobody can be identified. The methods and the ethics are as described.

She had lived with the question for ten months before she wrote to us, and like most people in her position she opened with an apology. "This is going to sound silly. There's probably nothing in it."

It is usually a fixed evening in the middle of the week. Infidelity is lazier than fiction makes out, and it tends to hide inside a routine that already exists. Her husband's routine was a Thursday squash ladder at a leisure centre, and it had been going for a year and a half. He came home showered, which she had first put down to good manners. What turned nothing into something was small: his racket bag had stopped coming in from the car. Ten months of a detail like that will wear a groove in anyone.

She had already done the things people do. She had looked at his phone once, when it was lying unlocked on the worktop, and found nothing, which somehow made it worse. One Thursday she had driven past the leisure centre, seen his car outside, felt ashamed of herself and gone home. But a car in a car park is not a man on a squash court.

The operation

In the first conversation we agreed the narrowest operation that could answer her question. One evening of surveillance, on the Thursday. One investigator to cover his departure from work and a second in position near the leisure centre, both sending position and imagery live to our own operations platform so that the handover between them was clean. No tracker went on his car. He was not our client, and our guide to GPS tracker law explains why a professional does not cut that corner. The plan needed only trained eyes, public places and timestamps.

Thursday one. He drove to the leisure centre, parked, went in and played squash. Our second investigator spent the better part of ninety minutes watching a car that did not move, and then he went home. We told the client exactly that. She cried with relief. Then she asked the question that separates people who want comfort from people who want the truth: "But he would be there most weeks, wouldn't he? Do one more."

Thursday two. He left work early. He did not head for the leisure centre. He drove west instead, to a quiet residential road a few miles away, and parked with the ease of a man who had parked there many times before. He was inside one of the houses for a little over two hours. The racket bag stayed in the boot. Our investigator recorded his arrival and his departure on timestamped video, from the public street.

Thursday three. The pattern held: the same road, the same ease, and this time a welcome on the doorstep that left no doubt about the nature of the visit. We stood the operation down there. Evidence has a job: enough for certainty, and enough for a court if it comes to that. Collecting more serves nobody, and we do not bill for voyeurism.

The report

Four days later she had a written surveillance report: factual observations, stills taken from the footage, a timeline accurate to the minute and an intact chain of custody. It was prepared so that her solicitor could use it in divorce proceedings without any argument about how it had been obtained. What she did with it was her decision, and she made it from facts, not from a feeling in her stomach at three in the morning.

Before the first evening she had asked what would happen if he turned out to be innocent. We gave her the answer we give everyone, the one the first Thursday briefly seemed to bear out: then you will know that instead, he will never learn that anyone looked, and that answer costs the same. Plenty of matrimonial cases end exactly there. This one did not. But ten months of not knowing ended either way.

If this is close to home: read about the signs of a cheating partner that matter and how a matrimonial investigation works, or tell us about it in confidence. The first conversation is free, and safe contact arrangements are agreed from the start.

Related reading: Covert surveillance · Matrimonial · Signs of a cheating partner