The constable knew him only vaguely but did have one conversational hook that was guaranteed to work. He made his way across to Morgan and sat at an adjacent two-person table, so they were diagonally opposite each other. The Special Branch officer raised his eyebrows in acknowledgement, then returned to his magazine as Wickens cleared his table of the detritus of the previous occupant. Finally ready to eat, the constable asked Morgan if he could borrow the ketchup. As it was passed across he said: ‘Crap performance in the rugby on Saturday, wasn’t it?’ Morgan was a known rugby fan and, after the disastrous England showing against France in a friendly last Saturday, Wickens guessed he would be happy to vent. For the next five minutes they talked through the game, the failings, the missed opportunities and the improvements that the coach should make.

Having put the world of sports to rights, Wickens asked: ‘Word has it you’ve got a big project at the moment.’

Morgan sighed heavily and looked around the room. ‘Too right. Drew the short straw on this one. Spending all my time on paperwork, filling out bloody benefit forms, council tax credit, you name it. Not what I came into the police for.’ He chewed ruminatively on his burger.

‘Some drug nark you’ve got to protect from the Albanians?’

Morgan shook his head and laughed. ‘I wish it was. Someone worth saving maybe, someone with at least a shred of human decency.’ He fixed Wickens with a glance. ‘I can’t say who it is.’

Wickens smiled. You just did. He finished his pasty, said goodbye, then headed out and back into the CID block. This time he was in better luck. The upstairs corridor was quiet, and he made his way along to the end to the Special Branch office. The door was shut, and from the lack of sound appeared to be unoccupied. He tapped and called hello. No reply.

He looked at the keypad. It was pretty old, requiring a four-digit code, plus the letter C to reset. He took out his LED torch and shone it at an angle. It clearly showed the four most heavily used digits on the keypad, because the black paint was rubbing off. Letter C, then five, nine, and particularly zero. In fact zero was almost unreadable. Most of the other numbers looked pristine. That was still a lot of combinations, but you could try as many times as you wanted. He tried a few but got nowhere.