M’s colleague R analyses a pattern of communications traffic around the Notts–Derby area, which shows some parallels with Leeds (although no contact). R presents her findings briefly, at the team meeting.

W, Z and P watch S, Q and E, through glass-walled meeting rooms, at their desks, on their way to lunch. They switch rabbits every couple of hours so as not to attract suspicion. On a smoke break, P tells Q that W is plotting something big with the rep on the Essex site. Keep it under your hat.

M sits in the canteen with a baked potato and a killer Sudoku, wondering what to do about the tennis coach.

Sure enough, Q can’t wait to spill the beans. After lunch Z sees her slip into the glass-walled office of A and sit down. A’s face is too interested to be listening to a variation in the monthly stats.

M decides to dodge the question entirely by letting her tennis lessons lapse for a while. It’s too cold for tennis anyway – time enough to restart in the spring.

J goes out in the early hours with an associate and does a doorway and a few paving stones on Hoe Street. Stencil-and-spray.

Z has been pulled into the union-side/management-side meeting, alongside P. They sit across the table from A, N and G. W is watching A, Z is watching N, and P is watching G (and, it is probably fair to say, vice versa).

Union side collectively has a lean and hungry look. It’s the walking, the cycling, the sheer quantity of energy expended upon subterfuge, espionage and counter-espionage.

W always wears a jacket to meetings with management. Not that she feels the need to suit up, but she needs somewhere to hide the mic. P and Z either side of her in shirtsleeves, P’s rolled above the elbow.

We want you to stop hacking us, says W.

We’re not hacking you, says management side suavely and blandly, in the person of A (hand-stitched Italian suit).

W changes the set of the questions and statements, reeling off request and accusation until she says: And of course we know that Q is a management spy – and the poker face slips momentarily. W sees it slip, Z sees it slip, and P sees it slip (they all compare notes afterwards, and this is what they saw, on the three-headed monster – each of its heads aligned, its reactions congruent, unanimous and legible).

(Only the certain prospect of mutually assured destruction keeps management side from cancelling W’s pass and escorting her off the premises with a cardboard box. Or in a cardboard box.)

So Q is the traitor. In the off-site meeting at a pub in Leyton, W, Z and P ponder what to do with her.