Someone came past, so Wickens headed off to the gents’, sat down in a cubicle and had a think. This was a bit like sudoku. He was fond of taking a paper with him into the loo and doing the brain-teasers. The last time he’d seen Morgan in the sports and social, it was his birthday. The Special Branch guy had bought everyone a pint, including him. What date was that? A birthday would make a memorable code, if not the smartest. It was some time in May. So let’s assume that was the 05. He couldn’t for the life of him remember what day it had been, but going for 09 would be a good start.

Of course, the door code might not be Morgan’s birthday. It could be his wedding anniversary, the birthday of a grandson or something else. It could also be the receptionist’s birthday, as she was probably in the office more than her boss. Wickens then realised that a six-digit date could be boiled down to four in two ways. One, by dropping the day or the year. Or two, by dropping preceding zeroes in day and/or month. Which to consider? Wickens returned to an observable fact, the worn zero. He decided to assume it was used twice in the code. He used a biro to write down some permutations on the palm of his hand, not wanting to sully the paperwork he was going to hand in shortly.

Wickens emerged from the gents’ just as a female in civvies emerged from child protection and went down the stairs. He could hear activity on the CID floor, but on his floor it was quiet. He pressed in 0509. Nothing. He went through various permutations, and finally, at 0590, the door opened. Inside, he closed the door, sat at the workstation and checked to see if Morgan was still logged in. No. When he tapped return, the prompt came up to enter log-in details. No point trying that without the password. He looked on the desk for a Post-it note with the code on. Nothing. Even Morgan wouldn’t be that dim.

He turned his attention to Morgan’s in-tray. There was a stack of documents, most of which appeared to be irrelevant to the Rollason case. Right at the bottom was a blank council tax benefit form. Wickens cursed Morgan for having not yet filled it in. Maybe it had only arrived today. He looked in the bin. It contained a torn window envelope. Inside it he found a standard cover sheet from the council enclosing the benefit form he’d just been looking at. It was addressed to: The Occupier, 63 Wexford Road, Staines.

That must be the address where Rollason was going.

What a find!